Warner Bros. has set Michelle Monaghan to star alongside Robert Downey Jr. and Zach Galifianakis in “Due Date,” the Todd Phillips-directed comedy.

Monaghan will portray the pregnant wife of a guy (Downey) who races home in hopes of arriving before she delivers their first child. He takes on a mismatched traveling companion (Galifianakis).

Phillips is producing through his Green Hat banner with Daniel Goldberg. Scott Budnick is executive producer. WB is partnered with Legendary Pictures on the film, and Susan Downey is an executive producer.

Monaghan next stars in “Trucker,” a film that opens Oct. 9 in New York and Oct. 16 in Los Angeles. She most recently completed “Somewhere” for director Sofia Coppola.