Los Angeles  - Iron Man star Robert Downey Jr will have more to laugh about come autumn when filming begins on the comedy Due Date, Variety reported Monday.

Downey is to play a first-time father trying to make it to the birth of his child on a road trip with his friend, played by Zach Galifianakis. The film will be directed by Todd Phillips.

Filming will start in late September in Los Angeles, New Mexico and Atlanta, Georgia. (dpa)