Peter Cullen is a Canadian-born voice actor best known as the voice of Optimus Prime in the "Transformers" animated and live-action film and TV franchise. The Montreal-born Cullen was a member of the first graduating class of the National Theatre School of Canada. Despite being classically trained, Cullen turned to voice acting in the early 1980s, earning roles on various French-Canadian children's programs. Soon major American studios came calling, and Cullen was cast in voice parts on dozens of animated shows, most notably as the voice of the mopey donkey Eeyore on "The New Adventures of Winnie the Pooh"; he has played the role in various Pooh-related films and TV shows since 1988. But Cullen's most memorable and enduring role was his voicing of Autobots leader Optimus Prime in the original animated TV series "The Transformers." Cullen's reedy voice proved so perfect for the part that he was cast in all of the franchise's subsequent adaptations, including a 1986 animated feature film "The Transformers: The Movie," and Michael Bay's live-action hits "Transformers" (2007) and "Transformers: Revenge of the Fallen" (2009).