Sylvester Stallone got so into a fight scene with Steve Austin while shooting 'The Expendibles' last year that he broke his neck, resulting in "a very serious operation afterwards."

Speaking to FHM magazine, the 'Rocky' icon revealed how intense the shoot went: "Man, it was seven guys, kicking each other's ass, one guy tougher than the next. 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."

He added: "I haven't told anyone this, but I had to have a very serious operation after wards. I now have a metal plate in my neck."