Justin Theroux is set to write the screenplay for Marvel’s sequel to this year’s summer action hit “Iron Man,” according to Variety.

Theroux is best known for his roles in “Mulholland Dr.,” “Charlie’s Angels: Full Throttle” and “Miami Vice.” He also wrote the script for Ben Stiller’s upcoming action comedy “Tropic Thunder.”

Marvel is also apparently wrapping up deals to bring back Jon Favreau as director and Robert Downey Jr. as the lead character. The release date for the sequel is set for April 2010.

At this stage, I’m not so sure what to think of this. I really love Theroux as an actor (especially in “Mulholland Dr.”), but with “Tropic Thunder” not yet in release, I have no clue whether he can be trusted as screenwriter. Plus, “Iron Man 2” is a pretty big deal.

Time will tell. At this stage, I’m pretty happy Marvel tries everything to speed up development and production for the second flick, although I sincerely hope they’ll approach the project with just as much effort.