He joins 'MADtv's Will Sasso as Curly (who, by the way, did not have curls). Moe (the mop-topped one) has not yet been cast.
Peter and Bobby Farrelly will direct and write the comedic biopic, which is scheduled for a 2012 release.
Hayes previously portrayed another famous comedian, Jerry Lewis, in the 2002 TV movie 'Martin and Lewis.' Since 'Will & Grace' wrapped in 2006, Hayes has guested on '30 Rock,' appeared in 'Soul Men' and 'Igor' and voiced "Mr. Tinkles" in 'Cats & Dogs: The Revenge of Kitty Galore.'