In comic books and in comic book movies especially, it often holds true that the hero is on as good as his villain.

And on the silver screen, comic book villains have a way of stealing the show from their more heroic counterparts, for good or for ill. However in the case of Marvel Studios' hotly anticipated "Iron Man 2" which hit theaters today, the question isn't so much whether the villains might overpower the hero on screen as much as it is whether they can keep up with Robert Downey, Jr.'s irreverent Tony Stark. Luckily, the bad guy side of this equation includes Academy Award nominee Mickey Rourke bringing all his grim power to the revenge-hungry Whiplash as well as acclaimed character actor Sam Rockwell spinning his own over-the-top take on arms dealer Justin Hammer.

Rockwell took time to talk to CBR News on the eve of "Iron Man 2's" U.S. opening about how he kept up with the standard set by Downey and director Jon Favreau in the first "Iron Man," what famous comic book villain performances he looked to in preparing for the role and how he kept his freewheeling improvisational style together during a challenging technical scene with Don Cheadle.

CBR News: When you come into a movie like "Iron Man 2" which aside from having a lot of big working parts and technical things that come with an action movie, there's a lot of detail paid to the characters and their portrayal in terms of being true to the comics. How do you balance those elements that the producers work on while still making Justin Hammer your version of the character?

Sam Rockwell as Justin Hammer in "Iron Man 2."Sam Rockwell: I think that at the end of the day we're there to please them and make them happy, but they want you to do your thing. They want you to bring your originality to the role. That's the way Kevin Feige and Jon Favreau and Jeremy [Latcham] at Marvel and Justin Theroux who wrote the script were encouraging making it your own, and I think that's what made the first "Iron Man" special. What made Tony Stark so unique is that Robert Downey, Jr. really brought his personality to the role in a way that I've never seen in a superhero movie with the protagonist. I don't know if I've ever seen that. It almost made Tony Stark an anti-hero like Jack Nicholson in "Five Easy Pieces." He's as interesting as Han Solo is. You don't usually see that. It's usually the bad guy who's more interesting than the good guy, and in this case Tony Stark is just as interesting if nor more interesting than the bad guy.

What's interesting about you coming in as the bad guy in 2 is that we'd all heard how Favreau has briefly discussed with you the possibility of your playing Tony Stark in the first movie. In a way, is this Justin Hammer a view into a parallel world where you played that role, but maybe a sleazy b-side to Downey's Tony?

Yeah. That's kind of what they asked for. They wanted Tony's competitor to be not unlike Tony, so this was my version of that.

As you got on set, you had to deal with a lot of technical stuff and technical jargon in some scenes. How do you balance those demands even verbally while also being able to adlib and play around with your fellow actors?

Well, I had a lot of help. Jon Favreau and Justin Theroux helped me a lot specifically the day with the guns. They added some new guns, and I'd memorized a lot and had done a lot of research with the guns. So on the day they added the new ones, so I needed an earwig, and Justin Theroux the writer was prompting me. We're old friend, and we go way back doing theater in Williamstown. So he's very good at prompting me. So some of the adlibs are mine, and some are Justin's, and some are Favreau's coming in between takes and saying, "Say this." Between the three of us, we sort of pulled that scene together. I was flailing because of the new guns they'd added. It was going south, and it came down to either being an earwig or some cue cards, and I credit Justin Theroux for feeding me a lot of the adlibs and me being agile enough to do stuff on the fly with Favreau being able to coordinate in between takes and telling us how to adjust. I think we really pulled it together, and I am pretty quick on my feet, so I was able to adjust to the two very smart men who were telling me what to do. And poor Don Cheadle is sitting there listening to all this. It was interesting. It was quite a day. It worked out, but it was hectic.

These movies do seem to be a team effort the way Favreau directs. Does that happen often on these kinds of action blockbusters?

You know, on movies I've done like this like "Charlie's Angels" and now "Iron Man," because the characters come from comic books and TV shows, they're really archetypes. They're not fully fleshed out. In a feature film, you have to step it up with human behavior. People are expecting that. There's been so many great superhero movies with so many great actors - Gene Hackman, Heath Ledger, Michael Keaton and Jack Nicholson. The standards are so high now. You get these great actors like Michelle Pfeiffer and Chris Walken to be in these movied, and the acting has to be pretty top rate. Heath Ledger won an Academy Award for playing a comic book villain, so that's a pretty high standard. But I think Downey and Favreau set the standard pretty high in the first one with Jeff Bridges, who's an amazing actor, as the villain. They're looking for these characters to come to life in a big way and in a different kind of way than they would in a comic book.

You've spoken about your relationship with Tony Stark on screen a bit. What's the opposite relationship like with Mickey Rourke's Whiplash? How do you play off of that to make him more threatening?

Just like I think Downey's so interesting that you have to step it up as this anti-hero protagonist, it's very similar to what Terrance Stamp and Gene Hackman did in the second "Superman." It's that same dynamic. Or kind of like Peter Boyle and Gene Wilder in "Young Frankenstein." That's the comedic dynamic there.

"Iron Man 2" is in theaters across North America today.