Stephen Colbert Will Voice a Genius Dog’s Enemy

Stephen Colbert arrives at 'The Late Show with David Letterman'. Photo: Kyle Blair / Splash News

Stephen Colbert has joined the cast of Mr. Peabody and Sherman, the 3-D update of an animated Rocky and Bullwinkle short about the world's smartest person (who happens to be a dog) and the boy with whom he time travels. (Modern Family's Ty Burnell will voice the former, The Amazing Spider-man's Max Charles the latter.) Colbert will play Mr. Peabody's "nemesis," Paul Peterson.