According to Rockwell, "Iron Man" director Jon Favreau originally considered casting him for the role of Tony Stark in the first film, but he's now on board to appear as Justin Hammer, a staunch corporate rival for Stark, in “Iron Man 2.”

"We had a phone conversation about it, and then I didn’t hear anything and that was it," Rockwell told MTV of early conversations regarding the part that eventually went to Robert Downey Jr. One blockbuster film later, the phone conversation was accompanied by an offer to play Hammer, and Rockwell accepted.

"They were like, we don't have a script but this is the deal and this is the character," the actor told MTV.

Rockwell had plenty of reason to follow the events in Favreau's film, even if he wasn't cast the first time around.

"I was a fan of the movie," he explained. "My girlfriend was in the first 'Iron Man,' Leslie Bibb." (Bibb played reporter and Tony Stark's quick fling Christine Everheart.)

Mixed signals flew around about Rockwell's place in the new script when his involvement was first announced, but he acknowledged that he will be playing the part of straight-from-the-comics businessman and all-around bad guy Justin Hammer.

"Yeah, he's a rival," Rockwell nodded. "He takes over all the weapons stuff after Tony's left."

However, the "Choke" and "Frost/Nixon" actor shied when pressed for any more story details.

"I don’t know if he takes over Stark Industries," he said. "I'm not really sure yet. He's a money dude. That’s about all I can say."

Asked if he would be excited to work with Golden Globe winning star of "The Wrestler" Mickey Rourke, Rockwell didn't even need to think about it. "Yes," he stated. "I never have met him. I've seen him a couple times."

Though Rockwell stopped short of confirming Rourke's casting.

"Is Mickey cast yet? I hope so," he told MTV.

Predictions have Rourke stepping in to play either the Crimson Dynamo or Whiplash. And i all goes well, Rockwell expects to be on the "Iron Man 2" set by spring.

"Mid-April maybe," he estimates. "In L.A., I think."

(For more on Sam Rockwell, check out yesterday's interview with Rockwell about the films he's bringing to Sundance this year.)

What do you think about Rockwell being cast in "Iron Man 2"? Are you anxious to see Mickey Rourke make an appearance too? Chime in with your thoughts on the next installment's villain below in the comments section!