Carol Burnett, Seth Rogen, Will Arnett, Isla Fisher, Dan Fogler, Amy Poehler, Dane Cook, Jaime Pressly and Jonah Hill have joined the voice cast of CGI animated flick "Horton Hears a Who," starring Jim Carrey and Steve Carell.

20th Century Fox Animation will release the comedy on March 14th 2008. Scribes Cinco Paul and Ken Daurio adapted the classic Dr. Seuss story for the bigscreen reports Variety.

Burnett will voice the role of the always skeptical Kangaroo. As previously announced, Carrey will voice the title character, while Carell will voice the role of the Mayor of Who-ville.