John Cusack and Sean Hayes have joined the voice cast of Exodus Film Group's CG-animated feature comedy "Igor" says The Hollywood Reporter.

Cusack replaces Christian Slater as the voice of title characterf Igor, a gifted scientist who is born with a hunch on his back and is forced to serve a cruel scientist named Dr. Glickenstein.

Hayes is playing Brian the Brain, a brain in a jar who is one of Igor's sidekicks and inventions. Jeremy Piven, Jay Leno, Jennifer Coolidge, Molly Shannon, Steve Buscemi and John Cleese have already been cast.

Tony Leondis will direct and Chris McKenna wrote the screenplay. The Weinstein Company will distribute the film next Halloween.