Ashton Kutcher really got into his role as a spy in the upcoming action-packed romantic comedy Killers. During a press conference, Collider.com reports that Ashton admitted to accidentally knocking out a stuntman and kicking actor Rob Riggle in the face during the fight scenes. Based on what Ashton says, it sounds like the movie is going to have some pretty fantastic action scenes.

"My stunt guy went to the hospital twice for jumping through glass. I did jump off a boat and I did most of the fight stuff. I bought one of those DVDs off the TV — those exercise tapes. And I put it in and watched it and got in shape. I did some fight training. I learned Krav Maga, Muay Thai, and Kali, which is a Filipino knife fighting."

In case you're wondering what Ashton works out to at home, it's the P90X system, which also counts Pink as a fan. The P90X system is a series of 12 targeted workouts (including yoga, circuit training, and plyometrics) and a nutrition program that promises to transform your body in three months. Ashton's wife, Demi Moore, first started tweeting that the couple were using P90X last year though she had only done the yoga component of the workout series. It looks like the idea of filming Killers was big motivation for Ashton to get in shape. Shortly after getting his P90X system he tweeted, "stepping up the work outs to 2 a days. time to get serious. I'm so paranoid about doing scenes with my shirt off."

As far as knocking out his stuntman goes, Ashton feels pretty bad: "That was a bad ordeal . . . I hurt a lot of people. I should have just let the stunt guy do everything, to be honest, and stuck to just making jokes."