Do-It-Yourself Theme Tune

""Yep, that's me!""

- Raven, That's So Raven

Essentially, this is when the theme tune of a particular show is written, sung or both by a member of the cast or someone else involved in the show in an otherwise non-musical context. Distinct from Theme Tune Cameo in that the theme may or may not actually appear in the show in an "in-universe" context, but in the real world it is written/sung by the real person.

See also Image Song.

Anime and Manga
Because the networks and studios notice that pop music and youth-centered stories are "in", this happens a lot in anime to the point where some companies won't hire voice actors unless they can sing as well.
 * The Magical Girl Lyrical Nanoha franchise has a tradition of having the opening theme (and an Insert Song) sung by Fate's voice actor (Nana Mizuki), and the ending theme by Nanoha's (Yukari Tamura).
 * Nana Mizuki does this a lot - see Blood C, Dog Days, Rosario + Vampire, etc.
 * Mahou Sensei Negima: The original, the Alternate Continuity and the Live Action Adaptation have the thirty-one girls of Negi's class singing the theme song. The first two switch what groups of girls are singing every so often, saving the whole class for the final episode, but the third uses the whole class to begin with. This doesn't stop them from including a version sung by the lead set of True Companions—Asuna, Konoka and Setsuna. Only on the Ending Theme single, though.
 * In fact, a lot of Anime Theme Songs fall under this trope.
 * Code Geass deserves a special mention here, though, because for one episode, the Ending Theme is a Dark Reprise sung by the voice actor of Lelouch, instead of a separate and seemingly disconnected group. Not even the last episode either; one episode later, the normal ending for this half is back as if nothing ever happened.
 * Repeatedly by Aya Hirano (before she had to stop for medical reasons), best known as the voices of Haruhi and Konata from The Melancholy Of Haruhi Suzumiya and Lucky Star, respectively. She performed both the OP and ED for Haruhi (and as Haruhi), and along with the other members of the main cast, did the OP to Lucky Star too.
 * Also played with within the universe itself with Mikuru being made to sing the theme song for the Stylistic Suck SOS brigade movie, "The Adventures of Mikuru Asahina".
 * For the "Second Coming" of Haruhi although, she sings the new ending "Tomare" as Haruhi, but she sings the new intro "Super Driver" in her own voice.
 * Rica Matsumoto has done six songs and one duet for Pokémon, where she does the voice of Satoshi (Ash).
 * This is a trend started almost immediately with the show, as she is the singer for the first opening theme.
 * Not to mention both playing Bikky in the FAKE OAV as well as singing the ending theme "Starlight Heaven."
 * The Sayonara, Zetsubou-sensei theme song are sung by "Zetsubou Shoujo-tachi" - a group made up of the lead female voice actors of the show, often with each singing one line solo.
 * The ending song of Shinkyoku Soukai Polyphonica Crimson S is sung by Haruka Tomatsu, the voice actress for Corti.
 * Sailor Moon's second (third if you want to get technical as the singers of the first changed in the third season) deserves special mention. Its lyrics were written by the Mangaka. The Second version of the first theme was also sung by the voice actresses of the Inner Senshi.
 * In a couple dubs (including the Dutch and the Swedish), Sailor Moon's voice actress even sang the intro theme.
 * The voice actors for the Keroro Platoon from Keroro Gunsou have done a number of the show's opening and closing themes, including a version of the first opening as performed by the Keroro Platoon.
 * Vic Mignogna, VA of the main character Dark, sang an English cover of D.N.Angel's theme song.
 * Subverted with the ending theme of Ouran High School Host Club. While he wrote the english translation, he wasn't allowed to sing it because his character, Tamaki, doesn't sing. There is still a version of him singing it here.
 * Sean Schemmel, the voice of Goku, sung the opening theme in the first Dragon Ball Kai DVD.
 * The OP and ED themes of Weiss Kreuz are sang by the four leads' seiyuus.
 * Dancougar has a version of its ending Burning Love sung by the Juusenki Tai. Fairly awesome.
 * All three opening themes for the Hidamari Sketch anime are sung by the main four characters' (Yuno, Miyako, Sae and Hiro) voice actresses.
 * In Kore wa Zombie Desu ka?, Iori Nomizu (Haruna) sings the opening theme for both seasons, while Rie Yamaguchi (Taeko Hiramatsu, a girl from Ayumu's class who frequently talks with him) sings the ending themes for both seasons.
 * Macross Frontier's 2nd OP, "Lion", sang by Megumi Nakajima (Ranka Lee) and May'n (Sheryl Nome).
 * The first OP "Trianguler" was sung by Maaya Sakamoto who played one of the Bridge Bunnies.
 * Ai Maeda performed all but one of the eight ending themes for Digimon Adventure through Digimon Frontier, as well the ending themes to some of the films; she portrayed Mimi Tachikawa in Adventure and Digimon Adventure 02, but didn't have any roles in Digimon Tamers or Frontier.
 * Ro-Kyu-Bu! is sung by the five main characters who so happen to have actually formed a group by the same name.
 * In the anime version of THE iDOLM@STER, Kotori sings one of the ending themes.
 * The song Yakusoku also fits, as the ending of episode 20, since, even though the girls are Idol Singers they are not song writers.
 * Maaya Sakamoto did this for her debut in Vision of Escaflowne.
 * She teamed up with Yoko Kanno again to do the ending of Wolf's Rain, "Gravity".
 * Megumi Hayashibara does most if not all the opening and ending themes for Slayers, either solo or with another singer.
 * She also does the opening for Slayers' sister franchise Lost Universe.
 * Roughly 83% of any anime that feature Megumi Hayashibara.
 * Infinite Stratos has the ending theme sung by the female main characters, with various versions as more characters are introduced.
 * In a possible inversion of this trope, TM Revolution, who did the first opening themes for Gundam Seed and Gundam Seed Destiny, was given a small role in the first series and a slightly larger and more plot significant role in the second. The singer for one of the ending themes was offered a similar opportunity but turned it down which is why Shiho Haas never has any lines in the anime.
 * Oku-sama wa Mahou Shoujo ending is sung by Kikuko Inoue, who's the voice for the slightly-older-than-standard Magical Girl Ureshiko.
 * Most people do not know that the theme song to Happy Kappy is actually preformed by Suguri and Kappy themeselves!

Film

 * Tom Hanks and Dan Aykroyd performed a Theme Tune Rap "City of Crime" for the 1987 Dragnet Revival Movie. They also did a music video, which must be seen to be believed.
 * It's really Hilarious in Hindsight considering the saga of Chet Haze, Hanks' white rapper son.
 * John Carradine, who played a brief role in Red Zone Cuba, also sang the theme tune. His singing voice makes it absolutely clear that he should have perhaps cut back on the smoking.
 * Also, his son David Carradine wrote and performed the theme tune to the film Sonny Boy.
 * John Carpenter composes the scores for many of his films (and also, as part of the Coupe de Villes, sang the end title song to Big Trouble in Little China).
 * Anita Mui was not only a famous actress in Hong Kong, but also a pop star in the early 1980s. Because of this, she ended up performing the theme for Heroic Trio.
 * Besides starring in, writing, directing and producing his movies, Charlie Chaplin wrote their music.
 * Director Mike Figgis often composes his own scores for his films.
 * Bryan Singer regular John Ottman not only directed Urban Legends: Final Cut, but also did the composing and editing (by trade, he is in fact a composer but also edits Singer's films).
 * Sylvester Stallone sang the theme song ("Too Close to Paradise") for his quickly forgotten Rocky follow-up Paradise Alley, the only movie ever to feature songs performed by Sly, Frank Stallone and Tom Waits!
 * This doesn't quite count since it wasn't actually included in the movie, but Clint Eastwood recorded and released a version of "Burning Bridges" from Kelly's Heroes.
 * Eastwood subsequently wrote themes for his films as a director (such as (Unforgiven) and then graduated to scoring them (apparently the likes of Lalo Schifrin, John Williams, Jerry Fielding and Maurice Jarre were just a warmup).
 * The title theme of Spider Baby is sung (well, hammily recited) by its star, Lon Chaney Jr.

Live-Action TV

 * Two Super Sentai series: Choujuu Sentai Liveman and Kousoku Sentai Turboranger. Both have their theme songs sang by the actors of their respective Red Rangers.
 * The Ending Theme of Hikonin Sentai Akibaranger, "Ashita wa Akiba no Kaze ga Fuku", is sung by Nobuo's actor Masato Wada.
 * Kamen Rider. Going all the way back to the original, several series have featured songs performed by members of the cast, usually The Hero or The Lancer. An incomplete listing: V3, Super-1, BLACK, Ryuki, Blade, Kabuto, Den-O, Kiva, Decade, Double and OOO. Special mention must go to Den-O, in which eight actors collectively sing two songs with five remixes, and Kiva, which featured a "limited band" called TETRA-FANG and fronted by the star.
 * A lot of sitcoms on Disney Channel have the theme song performed by their actors. A.N.T Farm, Good Luck Charlie, Hannah Montana, Sonny With a Chance, and Wizards of Waverly Place are examples of this.
 * It's easier to list which ones which are aversions of the trope: Lizzie McGuire, Phil of the Future, The Suite Life of Zack and Cody, and Shake It Up.
 * Nickelodeon does this a lot too. Drake Bell sings the theme song to Drake and Josh, Miranda Cosgrove sings the theme song to iCarly, Victoria Dawn Justice sings the theme song to Victorious, Keke Palmer sings the theme for True Jackson, VP, and Big Time Rush sings the theme for... Big Time Rush.
 * In the case of Victorious and Big Time Rush, their theme songs are sung by their respective characters (Tori Vega and the fictionalized version of Big Time Rush), owing to their statuses as musically-inclined sitcoms.
 * H₂O: Just Add Water' Season 3 has the original opening song, "No Ordinary Girl", sang by Indiana Evans, the actress playing Bella. Averted with the first two seasons (which were performed by Ellie Henderson in season one and Kate Alexa in season two).
 * The second season of My Babysitter's a Vampire has Vanessa Morgan (who plays Sarah) singing the OP, "Girl Next Door".
 * British actor Dennis Waterman has a history of doing this with the shows that he's in, including Minder and New Tricks. This is spoofed in a recurring skit on Little Britain, which invariably ends with Waterman losing work because of his insistence that he "write the theme tune, sing the theme tune..." to pretty much every job he's offered. (The other joke is the fact that the "Dennis Waterman" of the show, played by David Walliams, is repeatedly shown to be absolutely tiny, whereas the real Dennis Waterman is 5′9″ -- dead average.) The irony is that, although he sang the theme to Minder, he didn't actually write it. That was done by his wife of the time Patricia Waterman.
 * In Frasier, Kelsey Grammer, who stars as the eponymous Dr. Frasier Crane in the show, sings the closing theme song, "Tossed Salads and Scrambled Eggs".
 * The first theme to The Drew Carey Show, "Moon Over Parma", was sung by Drew Carey.
 * Joss Whedon wrote the theme song for Firefly. There's an alternate version of the opening in the DVD boxset where he sings it himself (albeit not that well).
 * Gene Roddenberry wrote the lyrics to the Star Trek: The Original Series theme (allegedly just to have a claim on its copyright and a share in the royalties).
 * As theme composer Alexander Courage wasn't keen on the lyrics and didn't come back to score any episodes of the series until after Roddenberry had left the show in the third season, it may not be just "allegedly."
 * Psych creator Steve Franks wrote and sang the theme song with his band, The Friendly Indians. He says that of all the times his name comes up in the show's credits, that's the one that makes him the happiest.
 * Every iteration of the Theme Tune of Mystery Science Theater 3000 was written and performed by the show's stars - Joel Hodgson wrote the lyrics that appear during his five seasons on the show, and all the variations that appear during the Mike years were written by Mike Nelson himself. (Considering that Mike wrote about three out of every five songs performed on the show, this is not actually all that surprising.)
 * "Final Frontier", the Theme Tune for Mad About You was written by Paul Reiser, who starred in the show. (Note that the show also featured a Theme Tune Cameo on one occasion.) Reiser also played piano in the recording of the theme song.
 * The theme tune to the 1970s American sitcom Alice, "There's a New Girl in Town", was sung by Linda Lavin, who portrayed the title character.
 * The theme to the 1980s British sitcom A Fine Romance (the song"A Fine Romance", written by Jerome Kern and Dorothy Fields) was sung by the show's star, Dame Judi Dench.
 * The theme song for How I Met Your Mother is sung by The Solids, a band that is made up of four guys, two of which are the show's creators, Carter Bays and Craig Thomas.
 * And one step further: In a sixth-season episode, the cast performs the theme song.
 * Folk singer John Tams played a regular supporting role in Sharpe and also wrote/arranged and sang most of its music.
 * Subversion: The theme tune of Two and a Half Men appears (in the show's initial opening credit sequence) to be sung by the titular cast, but producer Chuck Lorre confirmed in 2005 at a convention that actors Charlie Sheen, Jon Cryer and Angus T. Jones are only lip-syncing. The actual vocals were done by professional studio musicians.
 * And the one for Angus is apparently an uncredited Bernadette Peters...
 * (However, a TV spot for the show did feature the actors actually singing a set of gag lyrics to that title tune—evidently commemorating its move to daily syndication, as the lyrics began with Charlie Sheen singing, "EV-ry day, we're ON ev-ry DAY now..." Comparing Sheen's and Cryer's actual singing voices to the sound of the theme should have put this trope to rest for the show, but unfortunately Viewers are Morons.)
 * The Big Bang Theory's theme song, written and performed by the Barenaked Ladies, was mistaken for this by a few people who believed that Jim Parsons sang it.
 * The same thing happened with Smallville's theme song. The lead singer of Remy Zero, the band that performed "Save Me", bears an uncanny resemblance to Michael Rosenbaum (Lex Luthor).
 * Similarly, some people thought that Richard Sanders sang the WKRP in Cincinnati theme song. But he played Les Nessman and Word of God holds that the lyrics we're written from the perspective of Andy Travis, who was played by an actor (Gary Sandy) who had singing experience in musicals. It was actually performed by session singer Steve Carlisle.
 * The theme tune of 21 Jump Street was performed by Holly Robinson, who played Officer Judy Hoffs on the show (with the "JUMP!" shout provided by Johnny Depp and Peter DeLuise).
 * Walker, Texas Ranger. Chuck Norris. "Eyes of the Ranger".
 * The two theme tunes of Only Fools and Horses are sung by John Sullivan, the series creator.
 * Something that some people have noticed about the way Sullivan sings it is that he sounds like one of the main characters, Rodney. A few people (including this troper for a while) did indeed think that Nicholas Lyndhurst was the one singing it.
 * Subverted in Garth Marenghi's Darkplace: The opening is "based on melodies originally whistled by Gath Marenghi".
 * Both The Honeymooners and The Jackie Gleason Show featured theme music written by Jackie Gleason himself (Gleason put out numerous albums, but as a conductor rather than a singer).
 * David Naughton (better known as the "Dr. Pepper" guy and as An American Werewolf in London) both starred in and sang the theme song for the short-lived 1978 sitcom, Makin' It. Ironically, though the show was a flop, the song was a hit.
 * The theme song for Round the Twist was sung by Tamsin West, who played the original Linda.
 * Craig Ferguson sings the theme song for his late-night chat show The Late Late Show With Craig Ferguson, and also co-wrote the lyrics. And yes, he's really playing the drums in the opening segment.
 * Carroll O'Connor wrote the (never heard on the show) lyrics to "Remembering You", the closing instrumental theme song for All in The Family. Also, of course, the opening theme "Those Were The Days" was sung (on camera) by O'Connor and Jean Stapleton.
 * Paul McDermott, host of Good News Week, sings the theme tune (a cover of Hedgehoppers Anonymous' Good News Week).
 * The theme to Fresh Prince of Bel Air was sung by Will Smith.
 * The theme tune for the first season of Campion was sung by lead actor Peter Davison.
 * The theme song to Reba is somewhere between this and Real Song Theme Tune, since it's a partial rewrite of Reba McEntire's 2002 single "I'm a Survivor".
 * James May wrote the theme tune to his own series, James May's Man Lab. Given his musical background, it's not terribly surprising.
 * The opening theme from Bottom was written and performed by The Blue Notes, Adrian Edmondson's band. They also played the cover of "Last Night" that runs under the closing credits.
 * Beginning in its second season, The Brady Bunch had its theme song performed by the show's six child actors.
 * Lee Majors sang the theme song from The Fall Guy, "The Unknown Stuntman" (co-written by the show's creator, Glen A. Larson, who wrote or co-wrote the themes for many of his shows and thus paved the way for J.J. Abrams).
 * Everybody Hates Chris almost had one of these. Cast member Tichina Arnold wrote and performed her own song, but ultimately an instrumental theme tune was chosen instead. A small snippet of the song became the iconic "Everybody Ha-ates Chris!" riff at the act-breaks and end of every episode.
 * Greg Evigan shares ownership of this trope with Dennis Waterman, having done this four times, first with shortlived '70s sitcom A Year at the Top - justified as it was a show about a pair of musicians, played by Evigan and Paul Shaffer (!) - then with BJ and the Bear, My Two Dads (which he also performed on screen in one episode, leading Paul Reiser to wonder where he'd heard that song before) and P.S. I LUV U.
 * The Rentaghost theme tune was written and sung by Michael Staniforth, who played Claypole on the show.
 * Power Rangers Dino Thunder executive producer Douglas Sloan co-wrote its theme song.
 * Ultraman Leo has its first theme song performed by main star Ryu Manatsu. He did a rerecording a few decades later.
 * Nell Carter sang the theme song for Gimme A Break.
 * Queen Latifah peformed the theme for Living Single.
 * The theme song to The Doodlebops is sung by the titular band.
 * This also applies to its animated spin-off, Doodlebops Rockin' Road Show, whose theme song is also sung by the titular band but includes some spoken lines by Bus Driver Bob.
 * Happens a lot in the telenovela industry, where if you cast an actress with actual vocal chops you can get her to sing the telenovela main theme/opening song:
 * In Mexico, the careers of Thalia and Lucero are as tied as their time as main actress as the openings they sang and who launched their respective musical careers.
 * Natalia Oreiro got to international fame with both her main role and her opening for the telenovela Muñeca Brava
 * The theme song for Colombian telenovela Las Juanas is supposed to be in universe, and is sung by the actress who plays Juana Matilde.

Professional Wrestling

 * Shawn Michaels sang his own theme song after he broke off with the previous singer and his then-manager, Sensational Sherri. He used the same song for over a decade despite having dropped the "sexy boy" gimmick it was originally written for, and kept it right until retirement.
 * John Cena, due to the rapper gimmick he used to have, made his last two themes, one of which is still being used despite, as with Michaels, having long since dropped said gimmick.
 * R-Truth not only raps his own theme but puts on a live performance of said theme as part of his entrance. He's done this pretty much ever since he started wrestling, having done so in TNA as Ron Killings and in his first WWF stint as K-Kwik.
 * The WWE produced an album called WWE Originals which were songs all sung by the wrestlers or divas on the roster. Some were used briefly as actual themes for the respective wrestlers; I say briefly because, despite the valiant efforts of Jim Johnston, the world learned that professional wrestlers do not make for great singers.
 * Plus, despite "Put A Little Ass On It" being laughably terrible, Rikishi happens to be a really good singer.
 * Jillian sings her theme music "Sliced Bread," which adds to her character of being an absolutely awful singer.
 * Shannon Moore's final WWE theme song was an instrumental of a song he'd written & recorded.
 * Jeff Hardy's theme songs in TNA are written & performed by him. They were performed with his band Peroxwhy?gen.
 * Chris Jericho's band, Fozzy, has had their songs as themes for a few of WWE's pay-per-view events, most recently "Martyr No More" for the 2010 Royal Rumble.
 * Averted as far as Chris Jericho using a Fozzy song as his theme.
 * Borderline examples but there's a whole host of wrestlers whose catchphrases make it into their themes, usually at the beginning. Notable examples include The Rock, New Age Outlaws, Carlito, Finlay, and, most recently, The Miz.
 * Wrestlers in The Eighties often sung their own songs such as The Fabulous Rougeau Brothers, Hillbilly Jim, and the Honky Tonk Man.
 * Michael Hayes wrote and sang The Freebirds' "Badstreet U.S.A."

Video Games

 * The ending theme to Portal is sung by Ellen McLain in character as GLaDOS, complete with the electronic voice distortion and unsettling inflections of the original. Keep in mind that McLain is a trained opera singer.
 * Which gets shown much more
 * "Freesia", a prominent theme heard throughout Mega Man Zero 4, is sung by Rie Tanaka, who also voices the female lead, Ciel.
 * In BlazBlue, one of the fight themes is a vocal version of Noel's theme song. It was written and performed by, naturally, her voice actress.
 * Super Robot Wars OG Saga: Endless Frontier EXCEED main heroine is voiced by Nana Mizuki. And given her recent popularity, it wasn't a surprise that she sings the opening theme for the game.
 * In the Tokimeki Memorial series, the openings and endings of all Hibikino Saga games (Tokimeki Memorial 2 and its spin-offs) save for Leaping School Festival (and Dancing Summer Vacation for the endings) are sung by Junko Noda, the voice actress of the Hibikino Saga's main heroine Hikari Hinomoto.
 * Similary, most of the openings and endings of the games of the Classic Kirameki Saga (Tokimeki Memorial 1 and its spin-offs) are sung by Mami Kingetsu, the voice actress of this saga's main heroine Shiori Fujisaki. Exceptions are the Drama Series games, with the endings of Nijiiro no Seishun sung by Sachiko Sugawara, who voiced this game's heroine Saki Nijino, and Irodori no Love Song, all three possible ending songs being sung by Masayo Kawaguchi, voice actress of this game's heroine Ayako Katagiri.
 * In the Mitsumete Knight games, all the openings and endings (save for the Anne specific ending song, sung by her voice actress, Mariko Kouda) are sung by Hiroko Konishi, who voiced the series' main heroine Sophia Robelingue.

Web Original

 * All the music in Reynaldo the Assassin (theme tune and otherwise) is done by director/TalkingToHimself actor Oneclipleft.
 * "Do You Wanna Date My Avatar?", the single for the hit Web Original The Guild, was both written and performed by Felicia Day, the creator (and star) of the show. Well, co-written. She wrote the lyrics, and Jed Whedon wrote the music. The music video is peopled with the main cast of the show.
 * The Nostalgia Chick: Lindsay Ellis sings "Goodbye Internet's Rose" when Nella meets her fate at the hands of a ladder.

Western Animation

 * 6teen has the theme song sung by characters Wyatt and Jude.
 * Brendon Small was responsible for nearly all the music on Home Movies, including the theme song. He also writes the music for Metalocalypse and voices three of Dethklok's five members, including lead singer Nathan Explosion.
 * One of the DVD commentaries for Futurama has Billy West (in character as Fry) state that the theme song needed lyrics and sing the word "Futurama" in time to the music over the end credits.
 * The Disney series Pepper Ann has Kathleen Willhoite, voice actor for the main character, do the theme song.
 * Queen Alina in the last bit of Sonic Underground: "I long for my children but I have to wait. To act too soon could seal their fate."
 * As Told by Ginger's original theme was done by the title character's voice actress, Melissa Disney. After that, it was sung by singer Macy Gray.
 * My Little Pony: Friendship Is Magic is an interesting case, as most of the main characters have different vocal talent during singing roles. The trope is subverted by Twilight, Pinkie Pie and Rarity, but played straight with Rainbow Dash, Applejack and Fluttershy.
 * A slightly weird example of this trope, as Pinkie Pie and Fluttershy share a voice actress.
 * The theme for Family Guy is sung by the voice actors of the Griffin family.
 * Also, Mike Henry, who voices Cleveland, appropriately sings The Cleveland Show theme.
 * Seth MacFarlane, as Stan Smith, sings the American Dad theme song.
 * SpongeBob SquarePants: Patchy the Pirate, a character who appears in "special" episodes of the show, sings the theme song.
 * The theme song from South Park features lines by Stan and Kyle, Cartman, and an unintelligible one by Kenny. (the latter replaced by Timmy singing his own name in season 6)
 * Jane and the Dragon has Jane singing part of the theme song.
 * The Hong Kong Phooey theme song was sung by his voice actor, Benjamin "Scatman" Crothers.
 * Dastardly and Muttley in Their Flying Machines: Paul Winchell performed the theme song in character as Dick Dastardly.
 * Toopy and Binoo has Toopy sing the theme song.