Justin Theroux ("Mulholland Dr.") is keeping himself busy these days, and that's a good thing. The actor/writer/producer/director has just boarded Fox's upcoming romantic space comedy "Space Invader."

The Hollywood Reporter says the story follows a man who wants to space after he suspects his astronaut girlfriend is cheating on him with a spacewalker. Will Arnett is in talks to star in the project. 

Mike Lisbe and Nate Reger wrote the original draft, and Theroux is on board to complete a new one. Theroux, of course, co-wrote "Tropic Thunder" and the upcoming sequel "Iron Man 2."

I adored his edgy role in "Mulholland Dr.," but I also enjoyed him in "Miami Vice," "Inland Empire" and "Charlie's Angels: Full Throttle." He will soon be seen in "Your Highness."