The voice of Optimus Prime.
Peter Cullen is a Canadian voice actor who is prehaps best known as the voice of Optimus Prime in The Transformers (he would subsequently reprise his role as Optimus in Michael Bay's live-action Transformers film series and the Transformers Prime animated series). In addition, he has narrated and played Coran and King Alfor in the Lion Voltron series, the transforming spaceship/robot Ramrod in the 1980s anime series Saber Rider and the Star Sheriffs, Commander James Hawkins in the Vehicle Voltron series, Eeyore in Winnie the Pooh, the Predator in the original film, King Kong in the 1976 remake, and KARR in Knight Rider. He also holds the milestone of being the first person to provide the voice of Mario (in the Donkey Kong segments from Saturday Supercade), and for many years provided voice-overs for Toonami's promos. Cullen also voiced Monterey Jack on Chip 'n Dale Rescue Rangers for the first season, but was replaced by Jim Cummings for the rest of the series (it should also be noted that Cummings voiced Monterey Jack in the five-part pilot movie "To The Rescue").
Then when the news broke that he was to return to voice Optimus Prime, The Fandom Rejoiced (indeed, the trope was previously called "Cue Cullen").
Then when the news broke that he was not to return to voice Eeyore, Internet Backlash took over.
The Fandom Rejoiced once more, when he reprised the roll of KARR in the new Knight Rider series.
No relation to Bill Cullen, or that sparkly vampire.