Peter Claver Cullen (born July 28, 1941) is a Canadian voice actor. He is best known as the voice of Optimus Prime (as well as Ironhide) in the original 1980s Transformers animated series, and most other incarnations of the character. He has also voiced several other characters, including Eeyore in the Winnie the Pooh, Monterey Jack in Chip 'n Dale Rescue Rangers, and KARR in Knight Rider. In 2007, Cullen returned to the role of Optimus Prime in various Transformers media, starting with the first live-action film.