Mickey Rourke recently put on his Whiplash costume in preparation to work on Iron Man 2, and his rippling muscles certainly won’t be alone on the set. Rourke’s costume will show off his tattoos and an electromagnet that’s very similar to the one worn by Tony Stark. With leather and iron braces showing off his buffed-up bod, Rourke will no doubt make a big impression on the big screen.

But he’s not the only actor who will have audiences staring at the screen in wide-eyed wonder. Scarlett Johansson has packed on the muscular pounds for her role as Black Widow and star Robert Downey Jr. is in Iron Man-ready shape for the production.

Don Cheadle (who replaced Terrence Howard) and Gwyneth Paltrow will also be featured in the flick, which is scheduled to hit theaters on May 7, 2010.