Justin Theroux to Pen Iron Man 2

The director is on board.

All the stars have signed on.

Until this week, all Iron Man 2 needed was a writer.

But sources told Entertainment Weekly that actor Justin Theroux (pictured, Mulholland Drive, Six Feet Under) is taking on the script for the wildly anticipated sequel.

Marvel Studios won't confirm the deal, but Theroux has generated a lot of interest after early screenings of Tropic Thunder, which he co-wrote with Etan Cohen and Ben Stiller. Theroux made his directorial debut with last year's Billy Crudup/Mandy Moore dramedy Dedication. We'll let you know when this deal is finalized.