A gaggle of Hollywood stars have signed on to co-voice with Jim Carrey and Steve Carell in the upcoming animated version of Dr. Suess’ HORTON HEARS A WHO. Isla Fisher, Carol Burnett, Seth Rogen, Will Arnett, Amy Poehler, Dan Fogler, Dane Cook, Jaime Pressly and Jonah Hill will round out the voice cast for HORTON, which is being produced by Fox Animation and Blue Sky Studios (ICE AGE). The film follows elephant Horton (Carrey) who believes he hears voices on a speck of dust, which turns out to be a town called Who-Ville. Carell will play the Mayor of Who-Ville while Burnett will play Sourpuss Jane Kangaroo who bullies and teases poor Horton. Fox/Blue Sky will release HORTON on March 14, 2008, leaving them without an animated film in 2007, the first time since 2004.