A film actor playing a stickup man was almost shot by Long Island cops who thought he was committing a real robbery.

Nassau County Police Detective Mike Bitsko says cops were called to a convenience-store holdup in Bellmore at noon yesterday and saw a man pointing a gun at a clerk. They disarmed him, then learned he was an actor.

Director Fred Carpenter — shooting an indie film called “Jesse,” about a Nassau County detective — says he thought the cops were part of the scene until he recalled he hadn’t written anything in the script about police showing up.