The actor/writer will pen a draft of "Space Invader," an astronaut romantic comedy set up at 20th Century Fox.

Mike Lisbe and Nate Reger sold the project and wrote the original draft of the comedy, which centers on a man who decides to travel into outer space after he suspects that his longtime girlfriend, an astronaut, is cheating on him with another spacewalker. Will Arnett is attached to star.

Davis Entertainment, the production company behind a number of comedies, including "The Heartbreak Kid," is on board to produce with Principato/Young.

Theroux co-wrote the comedy hit "Tropic Thunder" and wrote the screenplay for the upcoming "Iron Man 2."

He's also on board to produce "Air Guitar Nation," a narrative version of the well-received documentary.

(Editing by Sheri Linden at Reuters)