 He voiced the pig Napoleon in a made-for-TV film adaptation of George Orwell's "Animal Farm" and guest starred in the "Simpsons" episode "Homer the Great" as Number One.Stewart also recorded a narration planned for the prologue and epilogue for Tim Burton's "The Nightmare Before Christmas" but the final movie used another voice (the original narration appears only on the first edition of the film's soundtrack).He plays a recurring role as CIA Deputy Director Avery Bullock, lending his likeness as well as his voice on the animated series "American Dad!