Downey signs on to cast of 'Due Date'

LOS ANGELES, July 25 (UPI) -- U.S. actor Robert Downey Jr. is set to play an expectant father on a road trip to witness the birth of his child in the new film "Due Date," film sources say.

Variety reported Friday the "Iron Man" actor will star opposite actor-comedian Zach Galifianakis in the new Warner Bros. comedy with Todd Phillips attached to direct.

Phillips tabbed the film as "a buddy comedy without the buddies."

Shooting on the new film production will begin in September with Arizona, Atlanta and Los Angeles tabbed as shooting locations.

The film will follow a screenplay written by Alan R. Cohen and Alan Freedland that has been revised by Adam Sztykiel.

Variety said Downey, 44, is currently promoting his new films "Sherlock Holmes" and "Iron Man 2" at San Diego's Comic-Con convention.