The Glee star has signed up to the cast, which includes Will Sasso, Sean Hayes and Chris Diamantopoulos, Deadline reports.
Her character will reportedly try to get the three brothers, Moe, Larry and Curly, who are first shown as children, thrown out of the orphanage.
Lynch is the latest addition to a project which has been in the works since 2007.
Johnny Knoxville, Sean Penn and Benicio Del Toro have all been in the running to play a brother in the comedy.
The actress will next be seen in sci-fi comedy Paul, starring with Nick Frost and Simon Pegg.