Credit: Jamie Trueblood

The real buzz behind action-thriller Jonah Hex (out June 18) doesn't involve the stylized shootouts: It involves Megan Fox's waistline.

In the DC Comics adaptation, Fox, 24 -- who plays the gun-wielding prostitute Lilah -- is forced to wear a very tight-fitting corset.

Just how constricting was the costume (which raised eyebrows last year after early film stills hit the web)?

"It's small," she tells MTV News. "We got it down to 18 inches. But in the action scenes, we loosened it up, because everyone was afraid I was going to pass out."

Her midsection ached even went she removed the corset.

"At the end of the day when we would take it off, it would leave these deep grooves, these deep indents from the boning in the corset," Fox says. "I'd have it for the whole next day. The next 24 hours I'd be imprinted with the corset. It hurts your ribs!"

By the end of the movie, she says the costume corsets "were all falling apart ... I beat them to hell."

Still, she says she'd slip into a corset again if the right role called for it. See the top 10 action babes.

"I do think there's a place for corsets," says Fox. "I think they should come back. They should make a reappearance. I enjoy them, but maybe I'm sick."