United Kingdom, May 10 -- Josh Hartnett was determined to "prove" himself as an action star in his 40s.

The 46-year-old actor stars in the new action-comedy movie 'Fight or Flight' and explained that he was desperate to do all of his own stunts for the flick.

Speaking to Us Weekly, Josh said: "I was like, 'Can I do this? I wanna see if I can.'

"I wanted to prove something to myself, physically, but also just give somebody pure popcorn entertainment in the best way possible, which is with a lot of humour and a lot of physicality and over-the-top, unexpected surprises. I'm very proud of it."

The 'Pearl Harbor' star was allowed to perform every stunt bar one and found it pretty "demanding" working on the movie.

Josh explained: "I had a ...