Actor turned scripter Justin Theroux will provide the words for Robert Downey Jr. and co to spew in Iron Man 2, as he’s officially been hired as the highly anticipated sequels writer. Theroux recently help pen the Ben Stiller comedy Tropic Thunder and will be well known to some folk from appearances in Miami Vice, Six Feet Under and Mulholland Drive. He’s kind of part of the comedic brat pack in Hollywood that involves Iron Man director Jon Favreau, Stiller and Downey Jr. etc; and is apparently quite the talented scripter. Tropic Thunder by the way, has been getting ecstatic reactions from preview audiences and fan boys alike after some preview screenings. The comedy opens here in September.