Jon Favreau has consistently been updating fans of Iron Man 2 via his Twitter page, recently writing " Leaving Edwards Air Force Base. Heading back to LA to finish out the week. My awesome crew worked their butts off. We got some great stuff." But what was he filming at the base? Well, a scooper for Corona Coming Attractions wrote in about seeing Sam Rockwell on the site, playing Justin Hammer, who is a rival billionaire industrialist to Robert Downey Jr.'s Tony Stark.

The source writes that Sam Rockwell was filming a scene with a combat drone that he (as Justin Hammer) develops. While the drone is no doubt Hammer's attempts to win military contracts against Tony Stark, it would be very surprising if there wasn't some sort of battle sequence between Iron Man and the combat drones. The source also says that "Sam is a great actor and funny as can be when he's improvising."

Iron Man 2, directed by Jon Favreau, will continue the tale of Tony Stark and his armored alter-ego as he continues his transformation from billionaire industrialist to super-hero. Robert Downey, Jr. will star as Tony Stark, with Paltrow returning in the role of his assistant Pepper Potts. Don Cheadle, Mickey Rourke, Sam Rockwell, Scarlett Johansson and Samuel L. Jackson also star. Iron Man 2 blasts into theatres May 7, 2010.