Sylvester Stallone has broken his neck during filming The Expendables

Sylvester Stallone required an operation for a hairline fracture and had had a metal plate inserted in his neck, as a result of filming a fight scene with wrestling star Stone Cold Steve Austin.

The film boasts some of the acting world’s biggest tough guys, including Arnold Schwarzenegger, Bruce Willis, Dolph Lundgren, Mickey Rourke and British actor Jason Statham.

The 63-year-old told FHM magazine that it became “so vicious” that it got out of hand.

“Man, it was seven guys, kicking each other’s ass, one guy tougher than the next,” he said.

“No joke, our stunt guys were begging for mercy.”

“Actually, my fight with Stone Cold Steve Austin was so vicious that I ended up getting a hairline fracture in my neck.

“I’m not joking. I haven’t told anyone this, but I had to have a very serious operation afterwards. I now have a metal plate in my neck.”

The film, in which Stallone was also a writer and director, centres around a team of mercenaries who embark on a mission to overthrow a dictator.

It also features actress Brittany Murphy, who died last month after collapsing at home.