Sam Rockwell, who plays Justin Hammer in Iron Man 2, will play a bar owner named Doc who joins in the pursuit of the aliens. Once Favreau and the writers (Alex Kurtzman, Roberto Orci and Damon Lindelof) learned that Rockwell was interested in the movie, they reconceived and expanded the role, which initially called for a heavy-set man.
Rockwell is joining Daniel Craig, Olivia Wilde and Harrison Ford in the film, based on the Platinum Studios graphic novel. The sci-fi Western explores what would happen if the traditional Old West enemies (cowboys and Native Americans) found the prairie attacked by aliens in mid-1800s Arizona.
With his Iron Man 2 promotional duties close to coming to an end, Favreau is said to be ready to kick off shooting this coming June!