Rockwell will play a bar owner named Doc who takes off the bar apron to help fight off the aliens. When Favreau found out that Rockwell was interested in the part, he had the writers enhance it substantially. It was originally made for a heavy-set actor.
Rockwell nearly steals the "Iron Man 2" show from an impressive cast of characters with his turn as arms manufacturer Justin Hammer. Playing the jealous contemporary to Robert Downey Jr., Favreau gave the actor free-reign to light up the screen. Hilariously there was mention of a Favreau-Rockwell feud at the press junket given that Rockwell was not on the movie's poster and that he had not attended the junket.
Favreau simply pointed out that Rockwell was doing a Broadway show and could not make it for the press junket. The director's wooing of the actor for his next project only makes their great working relationship all the more clear.