Woody Harrelson didn't think he could play a policeman because he is "anti-authoritarian".

The actor portrays cop Dave Brown in the Oren Moverman-directed movie 'Rampart', and he surprised himself as he doesn't have much "in Common" with his character.

He said: "I didn't think I could believe myself as a police officer, partly because I am a little anti-authoritarian and also because a big part of being an actor is what you connect from your own life to the character.

"I never felt I had much in common with cops, nor did I think my imagination was wide enough to see myself as one."

However, he admits his opinion changed as soon as he read The Script for the movie - about police corruption and misconduct - which also stars Robin Wright and Sigourney Weaver.

He told Film3Sixty magazine: "This is a guy who finds himself in a hellish quagmire and his descent ends in deep paranoia. I was psyched to play him in the end."