Dyeing for Your Art

Every job has its demands, and many people make sacrifices in their personal lives to advance their careers. However, actors and actresses sometimes experience some peculiar demands on their physical appearance, well beyond the common restrictions in other professions that may simply require neatly-trimmed hair of a natural color.

There are limitations to what can be done with stage makeup and padding. When performers make real changes to their physical appearance for a part, such that they look different in the mirror in the morning, that's commitment. That's Dyeing for Your Art.

This entry does not cover those actors and actresses who dye their hair all the time for professional or personal reasons e.g. Billie Piper, Gwen Stefani and the late Marilyn Monroe. They're Dye Hard.

Often overlaps with Oscar Bait nowadays. When the casting directors opt to have the actors focus on their performance instead of the character's appearance it's Ability Over Appearance.

Hair change:

 * Anna Faris is blonde, but dyed her hair black for the first two movies in the Scary Movie franchise as a parody of Neve Campbell in the Scream trilogy. She gave up on it by the third, which is helped considering the main "inspiration" for that one, The Ring, also stars a blonde. She claims on Canned Ham: Scary Movie that she told the casting people she was a natural brunette. No doubt she knew what happens to blondes in horror movies.
 * Bob Geldof actually shaved his own eyebrows off when playing Pink in the movie The Wall.
 * Charlize Theron died her hair black in order to play the title character in Aeon Flux
 * Gene Hackman was tricked into shaving his mustache to play Lex Luthor in Superman. Director Richard Donner had had a moustache shortly before he went to see Hackman about the part. Hackman didn't know he had shaved it off already, so Donner wore a false moustache that the makeup department made up for him. When he saw Gene, he told him that if he shaved off his moustache then he would shave off his own. So, Gene Hackman shaved off his moustache right in front of Donner and then said "Your turn" whereupon Donner pulled off his fake. Hackman was most displeased but, fortunately for Richard Donner, is quite undisposed to violence. On the other hand, Hackman flat out refused to shave his head to play the famously bald Luthor. Instead, he came up with the Running Gag of Luthor wearing a different wig in every scene (and wearing a bald wig when he's arrested).
 * Gretchen Mol, a blonde, played the title role in The Notorious Bettie Page. Page was a brunette. Whether Mol dyed her hair or wore a wig on her head is not known, but in a couple of brief nude scenes, the hair in her lower regions was definitely brunette. You may draw your own conclusions.
 * Ingrid Bergman cut her hair quite short for her role in For Whom the Bell Tolls, annoying Max Steiner, who wanted her to come back and re-shoot some Casablanca scenes with an original song in place of "As Time Goes By".
 * Jennifer Connelly dyed her usually raven hair blonde for the film Whats Wrong With Virginia.
 * Jerome "Curly" Howard of The Three Stooges shaved his head and his thick moustache specifically for his Stooge character when he joined the act.
 * Johnny Depp, in The Movie of Fear and Loathing In Las Vegas cut his hair to resemble his character's male pattern baldness. For added authenticity, Hunter S. Thompson personally shaved Depp's head. With a straight razor. While wearing a miner's headlamp.
 * Lindsay Lohan dyed her hair brown for Georgia Rule, then changed it to black for I Know Who Killed Me then she went blonde for Machete
 * Mikael Persbrandt, a swedish actor, has lost more than 30 pounds and buffed up noticeably for his role as the title character in Hamilton.
 * Monica Bellucci, for the Italian movie Malena, dyed her own hair first red (and cut it at shoulder length), then blonde, then sacrificed it completely for the scene where she is shorn by force by the other women of the city.
 * Naomi Watts, while she's naturally blonde, dyed her hair brunette for The Painted Veil. And that's the least of it.
 * Mel Gibson waxed part of his leg on camera for a shot in What Women Want.
 * Moe Howard of the The Three Stooges began dying his hair black once it started going noticably gray. He also allegedly dyed it reddish-brown for a period of time in his younger days.
 * Kristen Stewart dyed her hair black and cut it into Joan Jett's style to play her in the Runaways biopic.
 * Pauly Shore had his "trademark" dreadlocks shaved on-camera for In The Army Now.
 * Persis Khambatta shaved her hair for her role in Star Trek the Motion Picture.
 * Pete O'Hern grew a beard for the Peter Jackson film Bad Taste. Unfortunately for him, the film's low budget caused it to be filmed over four years, requiring him to keep the beard the whole time.
 * Rhiana Griffith shaved her head to play Jack in Pitch Black
 * Sofia Vassilieva (of Medium) shaved off her eyebrows and long blonde hair for her role as a cancer patient in My Sisters Keeper. Her co-star, Cameron Diaz, wore a bald cap for the brief scene where she shaved her head. Vassilieva reportedly got the role after Dakota Fanning stepped down, refusing to shave her head for the film.
 * Steve Carell's body-waxing scene in The 40-Year-Old Virgin was authentic. The results of the waxing are relevant to later scenes in the movie, so Carell had to have kept his chest hair in that condition for a while.
 * Steve Martin has been iconically silver-haired since the 1970s, but has dyed it darker for very few films including Little Shop of Horrors and Dead Men Don't Wear Plaid.
 * Telly Savalas shaved his head to play Pontius Pilate in The Greatest Story Ever Told -- and it became a trademark for the rest of his career.
 * Tom Felton, for his role in the Harry Potter movies as the blond Draco Malfoy, bleached his hair for ten whole years. James & Oliver Phelps dye their hair red to be the Weasley twins, as did Mark Williams to play Mr. Weasley.
 * Tom Cruise did it at least twice. He dyed his hair blond for Interview With a Vampire because Anne Rice (who wrote the novel) insisted that Lestat should be played by a blond actor. He also dyed his hair for the film Collateral.
 * Robin Williams:
 * He has bleached his hair blond three times: Popeye (1980), Toys (1992), and One Hour Photo (2002). He also dyed it red for August Rush.
 * He had his infamously hairy body waxed/shaved for The World According To Garp Hook, and Worlds Greatest Dad, to make him look younger in the first two cases, and as for the third, well, he was naked at the end. Old, fat, and naked is bad enough, we don't need hairy.
 * Yul Brynner shaved his head for The King and I, and (like Telly Savalas) didn't grow it back.
 * He also bulked up during The Ten Commandments because he didn't want to appear scrawny next to Charlton Heston....which is why he's so fit in The King & I.
 * Zachary Quinto shaved off most of his normally formidable eyebrows to play the role of Spock in Star Trek. Also, his Spock bowl-cut was real.
 * G.I. Joe the Rise of Cobra:
 * Sienna Miller, blond, dyed brunette to play The Baroness.
 * Rachel Nichols, brunette, became the redheaded Scarlett.
 * Star Wars Prequels:
 * Ray Park shaved his head to play Darth Maul in The Phantom Menace.
 * Ewan MacGregor actually grew his hair long so that the braid he wore as a Padawan would be his own hair, while the rest of the growth was shorn close, to play Obi-Wan. He also grew a beard for episodes 2 and 3.
 * Having your hair cut off is one thing but Vanessa Hudgens took this a step further by chopping of her own hair herself for the film Gimme Shelter.
 * Taylor Kitsch cut off his shoulder length hair in order to play a US Naval officer in the upcoming Battleship.
 * Joseph Gordon Levitt gave himself a buzz cut onscreen to play a cancer patient in 50/50.
 * There was a huge fan uproar when blonde Jennifer Lawrence and dark-haired Josh Hutcherson were cast to play the dark-haired Katniss and blonde Peeta in The Hunger Games. Director Gary Ross assured the fans that everyone would have the proper hair colors. Lawrence joked about it saying "I wasn't aware that everybody was so upset until I after I got my hair dyed, and people were like, 'Oh my gosh, blond hair can turn brown. Wow. It's a miracle!' "
 * Works for horses, too. For The Black Stallion, the production team needed a solid black Arabian stallion. Instead, they found Cass Ole, who had a star and socks. Therefore, out came the dye.
 * Tom Hiddleston dyed his naturally blond hair black (and straightened it) to play Loki in Thor, lightened it to a reddish-blond for Midnight in Paris, and darkened it again for The Deep Blue Sea. His poor, poor hair.
 * Molly Ringwald dyed her red hair black for the film adaptation of The Stand
 * One of the director/producers of Airplane! tells the story of being pretty much a punk kid at the time the movie was made, and hesitantly approaching Robert Stack and asking if just possibly the actor would be willing to die his hair for the movie. Stack laughed and made a comment to the effect "Don't worry about it, kid, when you bought me, you bought the package."
 * Anne Hathaway sacrificed all her hair completely for the scene in Les Miserables where Fantine sells her hair.

Weight change:

 * Andy Serkis, when he was cast to play Ian Dury in the recent biopic Sex and Drugs and Rock and Roll, spent time at the gym strengthening one side of his body so could realistically emulate Dury, who had a crippled arm and leg as a result of suffering polio in his childhood.
 * Aishwarya Rai had to gain weight for her role in Guru. She then lost 22 pounds in three days for her role in Dhoom 2.
 * Benicio del Toro, for The Movie of Fear and Loathing In Las Vegas, gained enough weight to become practically unrecognizable.
 * Bradley Cooper put on about 25 pounds so he could look like he could convincingly tackle and injure Vince Vaughn in Wedding Crashers.
 * Chris Evans bulked up and shaved to play Captain America in The First Avenger and The Avengers.
 * but averted in the post-test-screen pickups for The Avengers after Evans had regrown his facial hair. Rather than have to shave all over again for just a couple of scenes, Cap's face was concealed by a prosthetic or by his hand (most notably in the end-of-credits stinger ).
 * Chris Hemsworth, to play Thor, well... DAMN.
 * Christian Bale already had to buff up a lot for his role in American Psycho. A few years later he lost 63 pounds to appear in The Machinist (2004), making him unhealthily underweight. (He actually shot for the exact weight of the character in the script, even as the director and the producers told him he was skinny enough.) He then gained 40 pounds above his normal weight to play Batman in Batman Begins (2005). Then he lost 20 pounds of that. Later, he again became underweight to play an inmate in a Vietnam War prisoner camp in Rescue Dawn. Then he bulked up again to play Batman for the second time in The Dark Knight. Then he went skeletal again to play a crack addict in The Fighter (2010). Let's just say Bale's refined Dyeing for Your Art to an art form itself.
 * Daniel Craig buffed up, gaining 20 lbs of muscle to play James Bond in Casino Royale. However, he did refuse to actually Dye For His Art for Bond. He wouldn't dye his blonde hair to fit better with earlier screen Bond's darker hair colors.
 * Forrest Whittaker gained about 50 pounds for his role as Idin Amin in The Last King of Scotland.
 * Fifty Cent, known for his large physique, lost 55 lbs in 9 weeks by going on an all liquid diet and working out 3 hours a day in order to play a cancer stricken football star in Things Fall Apart.
 * Jared Leto resorted to fairly squicky methods (like drinking melted Haagen Dazs ice cream laced with olive oil and soy sauce) to gain the extra 62 pounds he needed to play John Lennon's killer Mark David Chapman in the film Chapter 27.
 * Jennifer Hudson gained 30 pounds to play Effie White in Dreamgirls.
 * Jennifer Jason Leigh got down to 86 pounds to play a girl suffering from an eating disorder in the 1981 telefilm "The Best Little Girl in the World".
 * Rain (Korean pop star) spent 8 hours a day in intense physical training, while eating nothing but salad and chicken, to play the lead in Ninja Assassin.
 * Ralph Fiennes packed on about thirty pounds to play the portly labour camp commandant in Schindler's List.
 * Renee Zellweger put on weight to play Bridget Jones...then lost it all and then some to play Roxie Hart...before putting it all back on again for Bridget Jones 2...
 * Richard E Grant actually gained weight to match the script's description of Withnail - only to be told by the director that he had to lose a stone if he wanted the role.
 * Sylvester Stallone put on 40 pounds for his role in the movie Cop Land by eating pancakes at a local diner three times a day. By the time he was called back for reshoots he already lost the weight. He's also taken to using growth hormones to maintain his impossibly muscular physique for various roles.
 * Taylor Lautner (Jacob from Twilight), to be able to be re-cast in the sequel, worked out religiously and gained 30 pounds of muscle. Much shirtlessness ensued.
 * Taylor Kitsch lost thirty pounds of muscle--and took up smoking!--to play suicidally-depressed photojournalist Kevin Carter in "The Bang-Bang Club". Kidney problems resulted.
 * Thomas Jane trained with the Navy SEALs for about half a year and gained more than twenty pounds of muscle for his role in The Punisher.
 * Tilda Swinton gained a significant amount of weight for her role in Michael Clayton. She didn't seem to mind, though, as it meant she could basically eat everything she wanted until she met her target look.
 * Vincent D'Onofrio gained 70 pounds of fat to play Private Pyle in Full Metal Jacket. The added weight later caused the ligaments in his knees to tear up during the obstacle course scene.
 * Three Hundred: the actors look like they're capable of incredible feats of strength and endurance. They were trained by a mountaineer named Mark Twight not just to look like that, but to be like that. They weren't just playing humans honed to Batman-like levels of physical might; they actually were humans honed to Batman-like levels of physical might.
 * Tom Hardy (five-foot-ten, 180 lbs) put on forty pounds of muscle to play British prisoner Charles Bronson in Bronson. If the teasers for The Dark Knight Rises are any indication, he's gotten even bigger to play Bane.
 * Mickey Rourke bulked up considerably for his role in The Wrestler.
 * Joseph Gordon Levitt bulked up and trained with stuntmen for his role in Inception so he could perform the stunts himself.
 * Robert Downey Jr gained 20 pounds of muscle to play Tony Stark by adding weight training and significant diet changes to his usual Wing Chun training.

Both/Other:

 * Charles Grodin has permanent scars on his wrists due to the handcuffs he wore in Midnight Run.
 * Charlize Theron put on about thirty pounds, partially shaved and bleached her eyebrows, and had her actual hair thinned and damaged to play serial killer Aileen Wuornos in Monster.
 * Choi Min-Sik, as the protagonist Oh Dae-Su in Old Boy, gained and lost considerable amounts of weight (repeatedly) to simulate a man being held in captivity for 15 years. Oh Dae-Su also kept track of how many years he had been confined by literally tattooing tally marks onto his arm. Unable to pull off the special effects required to depict this, Choi actually applied some of the tattoos for real on camera...using a piece of hot wire.
 * Edward Norton gained a lot of muscle for American History X, and lost most of it afterwards to play the insomniac, beaten down protagonist of Fight Club. Also for American History X, he as well as Edward Furlong shaved their heads to play convincing skinheads.
 * Ellen Page had her head shaved on camera for the film Mouth to Mouth, which led to her being mistaken for a boy when auditioning for Hard Candy. She nearly starved herself to look like (and feel the pain of) torture victim Sylvia Likens while filming An American Crime. A special feature on the Juno DVD shows her audition, and her face is so gaunt it's no wonder she had to gain back the weight in order to play a pregnant girl!
 * Demi Moore buzzed her hair down to the scalp on camera for GI Jane, and worked out religiously to simulate the effects of going through combat training.
 * Gary Oldman lost so much weight to play Sid Vicious in Sid And Nancy that he was actually hospitalized at one point. He also shaved his head for at least three of his other films: Meantime, Immortal Beloved, and The Fifth Element.
 * Georgina Cates dyed her hair and pretended to be a natural redhead to win the lead in the film An Awfully Big Adventure. She also changed her name, invented a completely fake past from Liverpool (the same city as the character was from) and pretended to be a teenager when she was actually 21 so that the casting directors would see her for the role again - the first time she auditioned she was told she wasn't suitable.
 * Halle Berry didn't bathe and wore the same clothes for several days to convincingly play a crack addict in Jungle Fever.
 * Hilary Swank went into hard training, and put on twenty pounds of muscle, for her role as boxer Maggie Fitzgerald in Million Dollar Baby. She also cut her hair, started binding (ie, flattening breasts) and generally acting like a boy for her role in Boys Don't Cry, to the point where her neighbours didn't recognise her and assumed that her brother must have been staying.
 * Jamie Foxx wore prosthetics over his eyes which made him blind for as many as 14 hours a day, and also learned Braille, in order to convincingly play Ray Charles in Ray.
 * Jim Carrey's been putting on a lot of weight lately for his upcoming role as Curly in the upcoming The Three Stooges movie.
 * However, Carrey dropped out of the film because he was worried about his health.
 * And he shaved his head for A Series of Unfortunate Events.
 * He also shaved his head and lost weight for scenes in the Andy Kaufman biopic Man On the Moon in which Kaufman was dying of cancer.
 * He also starved himself for two weeks to play Steven Jay Russell, a con artist  dying of AIDS.   Carry also shaved off his widow's peak to expose more of his forehead and look smarter
 * Keanu Reeves:
 * He shaved his head (including his eyebrows) as well as his body for the "real world" scenes in The Matrix. Those scenes were the last ones filmed, and were shot all together. The very last scene shot was the one where he first woke up in the real world, and he had lost considerable weight to give a slightly emaciated appearance.
 * The producers of Speed demanded he have a more respectable haircut (he had long hair), but balked when he showed up with a buzzcut, trying to insist he wear a wig for the film. The Director vetoed.
 * Gained 23 pounds to play a quarterback in The Replacements.
 * He also gained weight for The Last Time I Committed Suicide.
 * Matt Damon:
 * He grew as an actor in order to play the lead in Steven Soderbergh's The Informant!
 * He lost a dangerous amount of weight to play a drug addicted soldier in Courage Under Fire. This frail look almost made him lose the part of James Ryan.
 * Max Schreck shaved his head for Nosferatu and put some sort of hideous wiring around his eyes to make them bug out. Really.
 * Natalie Portman's head was shaved, on camera, for V for Vendetta.
 * She lost twenty pounds along with co-star Mila Kunis to play a ballet dancer in Black Swan, and took a year of ballet lessons before shooting began.
 * Nick Nolte grew out his hair and facial hair to achieve a crazed loner look for Hulk. It was in this unfortunate state that his infamous mug shot was taken. He also gained 50 pounds to play a paunchy detective in Q & A.
 * Peter Sellers' hair began to seriously gray in the late 1960s, so in many of his films from roughly 1969 onward, his hair is a dye job of some sort. A key exception is Being There, where he had his wife cut his gray hair short (figuring Louise, Chance's maid, would have been cutting it for him all these years). He also gained a good deal of weight, despite pre-existing heart problems, to reflect Chance's sedentary nature. Sellers was sensitive about his appearance and actually hated how he looked for the film, but felt it was what Chance should look like. (Some think losing the weight afterward contributed to his early death.)
 * Parker Posey had a dentist attach "train track" braces to her teeth to play a yuppie caricature in Best in Show. Michael Hitchcock as her character's husband settled for fake ones.
 * Rita Hayworth, was directed by husband Orson Welles to cut and dye her famous long red hair for The Lady From Shanghai.
 * And more hilariously, Orson Welles himself lost weight to play Falstaff in Chimes at Midnight. That's right. Orson Welles was SO OVERWEIGHT that he had to slim down to play freakin' Falstaff!!!
 * What's more, Rita was already a Dyeing for Your Art Dye Hard, because she was a natural brunette who had to dye her hair red as part of a career Race Lift to cover up the fact she was Hispanic.
 * Robert De Niro:
 * He famously gained 60 pounds to play Jake LaMotta in Raging Bull; he was one of the first actors to undergo such a transformation for an onscreen role. He gained the muscle training with the real Jake LaMotta until LaMotta decided he was ready to go pro - LaMotta later said that he thought DeNiro could have been in the Top 20 middleweights of all time.
 * He also packed on thirty pounds and had his hairline shaved back and receded to play Al Capone in The Untouchables.
 * He also put on a little bit of weight for the scenes in The Godfather Part II where his character returns to Sicily.
 * For Cape Fear, he paid a dentist $20,000 to seriously screw up his teeth to play long-term prison inmate Max Cady. It cost him $25,000 to have the damage fixed after the movie was over. He was also tattooed with vegetable dyes, which fade after a few months, and worked out to the point of having almost no body fat.
 * Taxi Driver is a subversion, as he didn't really get his head shaved in a mohawk (they still had scenes to shoot with his hair). However, he did shed thirty-five pounds to play the role of Travis.
 * Russell Crowe gained weight and shaved his head to make room for a wig for The Insider, and gained lots of muscle for Gladiator.
 * British film critic Mark Kermode points out that Crowe does this for a lot of roles and claims you can identify Crowe's 'serious' films based on his paunch.
 * Sigourney Weaver shaved her head for the third Alien movie, and dyed her hair red for Avatar.
 * Tom Hanks grew a rather lengthy, unkempt beard and lost 30 pounds for Cast Away. He gained the weight he was expected to lose during filming in advance, and the movie was put on hold while he lost it. He also slimmed down drastically to play an AIDS patient in Philadelphia.
 * Iron Man:
 * Robert Downey Jr. did some pretty hefty physical training to bulk up for playing Tony Stark in the first one. In an interview, he said his logic was something along the lines of "I'm not going to be able to do this for too much longer, so I might as well while I can".
 * Scarlett Johansson became the redheaded Black Widow (which also saw the return of another blonde dying her hair, Gwyneth Paltrow) for the sequel.
 * The Lord of the Rings:
 * Orlando Bloom had a Mohawk during filming in order to accommodate the widow's peak hairline on his Legolas wig.
 * Also he, along with the rest of the cast of Black Hawk Down had his head shaved by military barbers and participated in boot camp to prepare.
 * Brad Dourif had his eyebrows repeatedly shaved to play Grima Wormtongue.
 * Sean Astin put on weight for Sam too.
 * Spider-Man:
 * Kirsten Dunst wore a wig for the first movie, but dyed it for the second (and possibly third) one.
 * Tobey Maguire had to gain some muscle to play Spider-Man. His worst experience was for the second movie, because he had become very thin to play a jockey in Seabiscuit.
 * Bryce Dallas Howard (Gwen Stacy) was the opposite of Dunst: redhead becoming blonde.
 * Spider-Man 3 scored the hat-trick of hairdyes when you factor in Elizabeth Banks as Betty Brant (blonde to brunette).
 * Topher Grace gained 24 pounds of muscle and bleached his hair to play Eddie Brock in Spider-Man 3.
 * Thomas Hayden Church put on 28 pounds of muscle and dropped 10 pounds of fat for Sandman.
 * Emma Stone is known as a redhead, but reverted back to her natural blonde to play Gwen Stacy in the upcoming Spider-Man reboot - before her casting was officially announced, it was rumoured she'd be playing the red-headed Mary Jane Watson.
 * Super Troopers: all the members of Broken Lizard grew mustaches and built up their forearms to give themselves a more stereotypical highway patrolman look. One scene features Kevin Heffernan using one of the workout tools they used.
 * Hairspray:
 * Zac Efron dyed his hair (dark) brown and put on 15 pounds.
 * Amanda Bynes took two hours to get her pigtails right, and risked losing her teeth from eating around 40 lollipops a day. Yeesh!
 * For the X Men movies, Hugh Jackman, Liev Schreiber, and Ryan Reynolds worked out to get ripped bodies, and Famke Janssen dyed her hair red.
 * To play Lisbeth Salander in David Fincher's remake of The Girl With The Dragon Tattoo, Rooney Mara chopped her long brown hair off and went to a dyed-black pixie cut, bleached her eyebrows, got both ears pierced four times, and got her lip, eyebrow and one nipple pierced as well. Say what you will about her, she doesn't do things in half measures.
 * Noomi Rapace (the actress who played Salander in the original Swedish films) deserves mention also. In addition to performing image alteration similar to Mara's, Rapace took up smoking for real during filming and took to dressing and acting "in-character" even when not on camera...to the point where family and friends began to worry as to her sanity. There's a very good reason she refused to do the role again for the American remake.
 * Averted in Once Upon a Time In The West. Henry Fonda, Cast Against Type as the Complete Monster Frank, initally wanted to drastically change his usual appearance by growing a beard and wearing brown contacts. Sergio Leone told him not to do it, as the shock of seeing Fonda as such a character was exactly why he hired him, and it would work best if he looked like he usually did.
 * Lon Chaney Senior took this to Up to Eleven
 * Dragon the Bruce Lee Story: To play Bruce Lee, Jason Scott Lee (no relation) trained with Jerry Poteet, who was a student of the real Lee.
 * The whole cast of The Wizard of Oz had to suffer with long shooting schedules and the hot lights required for early Technicolor. But three in particularly were fit most for the trope due to heavy make-up: Margaret Hamilton (could not eat and remained on a liquid diet, the copper-based Wicked Witch make-up got burned by malfunctioning pyrotechnics), Bert Lahr (had the liquid diet before he decided to get his make-up redone everyday, the Cowardly Lion suit made of real lion skin made him sweat profusely) and Jack Haley (the Tin Man suit was so stiff that he had to lean against a board to rest; the make-up needed some changes as it previously caused the actor Haley replaced to get hospitalized).

Hair change:

 * Adrian Pasdar grew a beard for the second season of Heroes. It was so impressive it had its own nickname.
 * Ariana Grande dyed her hair the color of red velvet cupcakes when she was cast as Cat Valentine in Victorious, to avoid having a cast completely of people with dark brown hair.
 * Ashley Tisdale had her hair dyed from brunette to blonde when she did The Suite Life of Zack and Cody. She later went back to being brunette after the High School Musical movies, but when she reprised her role as Sharpay in Sharpay's Fabulous Adventure, she instead used a blonde wig, averting the trope.
 * Bruce Boxleitner grew a beard that he found very annoying for the last season of Babylon 5, at J. Michael Straczynski's insistence that his character be visually different to reflect his development.
 * Chloe Annett, The Other Darrin in the role of Kochanski on Red Dwarf, had her long light brown hair cut short and dyed dark brown so that she'd look more like her predecessor Clare Grogan when she took the role in Series VII. In Series VIII, she had her own natural hair (despite the fact that the series premiere took place a matter of minutes after the previous series' finale - the change in appearance was never commented on).
 * Daniel Roche, a child actor known for having long hair in sitcom Outnumbered, got a short back and sides to star in Just William.
 * Diane Neal, as Casey Novak, never had the same hair color two seasons running, ranging from painfully Alex Cabot-esque blonde to bright red.
 * Eva Habermann dyed her hair blue to play Xev Bellringer on Lexx. Due to hair damage from the dye, she had to switch to a wig in the second season.
 * Gillian Anderson was asked to cut and dye her naturally long blonde hair into an auburn bob for the part of Dana Scully on The X-Files.
 * Groucho Marx never had a mustache most of his career; the comedic one he's always depicted with was a fairly obvious greasepaint job. When You Bet Your Life came along in his late career, he grew one so he could be at least partly recognizable.
 * Jason Lee grew Earl's trademark 'stache for My Name Is Earl, because he felt like the character needed one.
 * James Marsters dyed his hair platinum to play Spike on Buffy the Vampire Slayer and Angel.
 * Alyson Hannigan dyed hers to add more red to it for her role as Willow. It's naturally red, but a bit more auburn than Willow's.
 * Kasey Rogers, the second actress to portray Louise Tate on Bewitched, originally dyed her red hair dark brown to more closely resemble Irene Vernon, the actress she replaced. In later episodes, she reverted to her natural hair color.
 * Katie McGrath dyes her naturally blonde hair very dark and "stays out of the sun" to play Raven Hair Ivory Skin Morgana on Merlin.
 * Leighton Meester, a natural blonde dyed her hair chestnut brown because Blair Waldorf is described as a brunette in the Gossip Girl books.
 * She actually dyed her hair before she even got the part, because people at the studio who didn't want her to be Blair kept using her hair color as a reason that she shouldn't be cast.
 * Linda Thorson joined The Avengers as a Suspiciously Similar Substitute for Emma Peel. She was supposed to dye her hair blonde to differentiate her from her predecessor, Diana Rigg. The treatment made her hair fall out, so in some early episodes she's wearing a brunette wig, while in others (e.g. "All Done With Mirrors") her hair is very short.
 * Mackenzie Crook, who played Gareth in The Office, said that he has his character's unflattering bowlcut in his wedding photos, captured for posterity.
 * Majel Barrett, having been fired from the original Star Trek the Original Series pilot, cut and bleached her hair blond to audition for the role of Christine Chapel. Strangely, The Powers That Be didn't seem to notice.
 * Mark-Paul Gosselaar, whose hair color had darkened as he went through puberty, had to dye his hair and have touch-ups before each episode of Saved By the Bell. His dark roots usually showed though.
 * Michael Rosenbaum shaves his head to play Lex Luthor in Smallville.
 * Mike Lookinland, the auburn-haired child actor who played Bobby Brady on The Brady Bunch, was forced to dye his hair jet black to more closely resemble his TV father and brothers. In later seasons though, his natural color returned.
 * Mollie Sugden, who played Mrs Slocombe in Are You Being Served, had to have brightly-coloured hair which changed colour every episode. At the start this was done by actually dyeing Sugden's hair, but the treatment caused reactions and hair loss so the production switched to a series of brightly-coloured wigs from then on.
 * Natalie Dormer is a natural blonde - she dyed her hair black to play Anne Boleyn on The Tudors.
 * Rose McGowan dyed her hair brown for a part as a brunette in Charmed but a potion blew up and she was a red-head again.
 * Sacha Baron Cohen's actual facial hair is used for Ali G and Borat.
 * He also shaved his body hair to play Bruno.
 * Stephen Colbert had his head shaved to show solidarity for the troops when he took his show to Baghdad, then made a Running Gag out of complaining about how slowly it was growing back.
 * Virginia Hey shaved her head and eyebrows to play Zhaan in Farscape. She was eventually forced to leave the show because the huge amounts of makeup were causing her serious skin and kidney issues.
 * Doctor Who:
 * Mark Strickson, to play Vislor Turlough, was required to dye his blond hair red. This was to avoid him being confused with the blond Peter Davison in long shots. This was a peculiar worry of the producer's, who also feared the audience would confuse Tegan (a twenty-something woman who normally wore a lilac air hostess uniform) and Adric (a teenage boy usually to be seen in a yellow and red pyjama-like costume). Well, they do both have brown hair.
 * Peter Davison had his hair highlighted to play the title role. This is particularly noticeable as it is considerably darker during his brief appearance at the end of Logopolis than it is in Castrovalva, despite the fact that the latter is supposed to follow on immediately after the former.
 * They must have loved this trope in The Eighties: Colin Baker was blonded up, too.
 * Louise Jameson wore brown contacts during her first season of playing Leela. At the end of Horror of Fang Rock, the first serial of her second season, an in-show reason was given to have have her eyes change from brown to blue (her natural color).
 * Skins:
 * Lily Loveless, naturally brunette was bleached twice and toned to peroxide blond.
 * Megan Prescott's hair was dyed bright red to match her twin Kathryn, who had walked in with her hair already dyed red: The stylists decided to Throw It In.
 * Dakota Blue Richards cut her hair short for the role of Franky Fitzgerald.
 * Bryan Cranston shaved his own head on camera for Breaking Bad, though the scene was cut out.
 * Castle has an in-universe example with Natalie Rhodes. In order to be closer to Beckett's style (since Nikki Heat was based on her), she dyed her hair from blonde to brunette.
 * Pasquale Finicelli, an actor with naturally dark brown hair, had to dye it blond with a red forelock in order to play Mirko in the Italian teen soap opera Love Me Licia.
 * In Sherlock, both Benedict Cumberbatch (as Sherlock Holmes) and Mark Gatiss (as Mycroft Holmes) dye their hair black. They're both naturally ginger.
 * In the Granada Sherlock Holmes series, David Burke, the first Dr. Watson, dyed his grey hair and mustache auburn to make himself look much younger.
 * William Petersen kept his almost-white hair dyed darker to a gray shade for the later years of his role as Gil Grissom on CSI. It does appear a bit more natural in his season 11 cameo, however.
 * Adrian Paul used hair extensions for the first season of Highlander the Series and then grew it long for the next four. He cut it for season six because he was tired of caring for it.
 * Poppy Montgomery decided to become a redhead for Unforgettable.

Weight change/Other:

 * Jewel Staite was asked by Joss Whedon to put on 20 pounds to play Kaylee in Firefly, which she did. She lost it when the show was canceled, but did not regain it for Serenity. She also dyed her hair to play Dr. Jennifer Keller in Stargate Atlantis.
 * Kiefer Sutherland got a real tattoo for 24. In one season, Jack Bauer gets a gang tattoo. In order to avoid hours of makeup every time, Sutherland just got the real thing done.
 * Margaret Cho, shooting her short-lived sitcom All American Girl, was forced to lose weight to play herself. She lost 30 pounds in three weeks and her kidneys collapsed as a result.
 * Pauley Perrette got a number of her NCIS character Abby Sciuto's tattoos done for real (but not all of them).
 * She already had a lot of tattoos. The spiderweb is not real.
 * Her hair has also been dyed from her natural blonde to the more well-known black - for the past seven years.
 * Summer Glau was accidentally hit in the face with a brass casing that left a small scar while training to handle weapons for The Sarah Connor Chronicles. Rather than have it removed by makeup, Summer instead kept it to help make the character of Cameron more convincing.
 * Tim McInnerny, in the fourth series of Black Adder, gave his character Darling an eye twitch that became a real tic over the repeated takes. He didn't lose it until months after the series ended.
 * Tom Fontana, series creator of the prison drama Oz, volunteered to be the man receiving an upper-arm tattoo of the show's logo. He even asked for the tattooing to be re-shot so as to get it perfect, but the tattoo artist refused, claiming if he applied the needle any longer, Fontana might die.
 * Tricia Helfer dyed her dirty blond-brown hair platinum to play Six on the reimagined Battlestar Galactica Reimagined, but she switched to a wig a few episodes into the first season because the bleach was causing hair issues (namely, falling out in chunks), which explains how she was able to be both natural haired Gina and platinum Six.
 * In the same series, Edward James Olmos wore blue contact lenses and Jamie Bamber dyed his dark blond hair brown, so that they would look more like father and son.
 * Jamie Bamber dyes his hair brown for many of his roles.

Music

 * Enforced with the rather shameful example of castrati. Back in the earlier days of Opera, when prepubescent boys with good singing voices would be castrated so that their voices wouldn't break (and therefore ruin their ability to hit the high notes that composers were so fond of putting in their compositions). This practice eventually died out: castrati were frequently cast as women--which made sense in an age where few women took up acting or singing in operas, which was seen as unladylike somehow. When female opera singing became more socially acceptable, and stealing the manhoods of little boys was not, the practice gradually disappeared, and was finally banned in its primary center (Italy) in 1861 (shortly after unification).
 * The practice is also a bit of Fridge Horror when you consider that for many boys who underwent "the operation," other factors--ranging from the occasionally-lethal doses of opium administered to block the pain of the procedure to simple "your voice isn't good enough"--prevented them from actually singing upon reaching adulthood.
 * Till Lindemann got a hole pierced in his cheek so he could run a LED light through it for most of Rammstein's "Ich tu dir weh" video (It closed up during filming when he lost the plug keeping it open.).
 * Gerard Way of My Chemical Romance bleached his hair white to portray a dying cancer patient in the black parade era. This temporarily made him a White-Haired Pretty Boy
 * Vocal fold operation is quite common for professional cante flamenco singers.

Professional Wrestling

 * Anytime someone loses a Hair-vs-Hair match.
 * Arguably the best example was Molly Holly. Originally during Wrestlemania XX, a Women's Championship match was not on the card. She decided that she needed to do something to get the Women's Title on Wrestlemania, so she offered her hair for it.
 * Molly did this more than anyone. When she initially debuted as Miss Madness in WCW she bleached her hair blonde and glammed herself up to look like a pageant queen. And when she went from sweet blonde Molly to her self-righteous prude character she cut her hair, dyed it brown and started wrestling in conservative ring gear. She even re-bleached her hair again for her reappearance at Wrestle Mania 25.
 * Kurt Angle, after losing a Hair-vs-Hair match, wore a (bad) toupee for a while. In true heel fashion, he would freak out when someone pointed out it was a toupee. Once the toupee comedy ran its course, he debuted his bald look by whipping the toupee off and smiling until the fans quit heckling him.
 * For a good amount of time, Natalya Neidheart dyed her naturally blonde hair red, because there were too many blonde Divas in WWE. She's since gone back to her natural hair color, but with pink streaks as part of her new gimmick embracing her Hart heritage, whose signature colours were black and white.
 * John Tenta had his LSU tiger tattoo changed to a shark to fit his new gimmick. Later as part of an angle he shaved one half his head bald, leaving the other half bearded and skulleted.
 * Jillian Hall felt she wanted to get breast implants when she was in OVW and Jim Cornette decided it would become her gimmick so she bleached her hair blonde as well and the storyline was that the implants leaked into her brain and turned her into a Dumb Blonde.
 * Roxxi Laveaux in TNA dyed her hair various colours to fit with her Voodoo Queen gimmick. The dye ended up stripping her hair which led to another example of the trope - where she infamously had her head shaved at the 2008 Sacrifice PPV.

Theater

 * Tim Curry dyed his hair blonde during the stage production of The Rocky Horror Show.
 * Megan Hilty dyed her hair brown near the end of her Broadway run as Glinda in Wicked, and kept it through her run as Mary in The Musical of Vanities, but wore blonde wigs for both characters.

Theme Parks

 * At Halloween Horror Nights 2010, all of the actors in the Havoc: Dogs of War house were required to shave their heads to more accurately play genetically-altered supersoliders, including the girls. This has led to some surprisingly good reviews of the house so far, despite being predicted as this year's flop, as the cast arguably consists of the most dedicated performers in the whole event. Some of them have gone slightly nuts in their performances and risked damaging sets.

Videogames

 * Reuben Langdon had his hair dyed white for the Japanese live-action commercial of Devil May Cry 3. And he looks ALMOST exactly like Dante.

Web Originals

 * Jermaine of Awkward got his buzzed mohawk look to look authentically douchey. He had to keep it that way for two months.

Western Animation

 * Referenced in-universe in the The Simpsons. In one episode, Rainier Wolfcastle is seen coming out of a convenience store, grossly overweight and in the middle of gorging himself further. Wolfcastle informs his onlookers that he's preparing for a role as a fat secret agent.