John Cusack and Sean Hayes have joined the voice cast of Igor.
Cusack replaces Christian Slater to voice the title character of 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.
The voice cast includes Jeremy Piven, Jay Leno, Jennifer Coolidge, Molly Shannon, Steve Buscemi and John Cleese.
Directed by Tony Leondis the film is set for an Oct. 24, 2008, release.
John Cusack and Sean Hayes have joined the voice cast of Igor. 
