The Expendables 2 cast competed over everything, even the size of their watches.

The cast for the sequel to the hit action movie includes legendary actors Sylvester Stallone, Bruce Willis, Jason Statham, Jean-Claude Van Damme and Arnold Schwarzenegger. At the London press conference prior to the film's European release this week, the ageing actors admitted that they liked to challenge each other on set.

"It was competition all the time," Arnold revealed to Cover Media. "We competed who has the biggest muscles, the best body, the least amount of body fat, who has the biggest gun, who kills the most people, and even who has the biggest watch..."

Sylvester Stallone agreed that the macho men were all over competitive in an attempt to impress each other while filming. The actor believes it is no bad thing and encouraged some healthy rivalry between the all-star cast.

"There was lots of competition on set, no one wants to be second, that's why everyone pushed really hard," he explained. "Being competitive is why we are so established and the people that we are. We want to be the best and usually we are."

The movie marks Arnold's return to the big screen following an eight-year break from movies while he was working in politics. The former Governor of California admits he had to ask for some assistance while shooting his action scenes.

"Everyone on set was very helpful to me. I have been out of the movies for eight years so they went overboard with the help. I didn't know how to hold a gun anymore," Arnold joked. "Everyone came together and helped which was very terrific but at the same time we were very competitive. If you grow up thinking you have you be the best then the more you compete, then the more your challenged, the more you challenge the more your performance improves. You have to always step it up."