Police called to Cool Stop Groceries for an armed robbery earlier today were surprised to find the gunman was actually an actor playing a part in a movie.

"We knew they were shooting in Nassau County, but they told us it would be tomorrow," Nassau Police Public Information Officer Vincent Garcia said.

Coincidentally, the movie being shot by Long Island filmmaker Fred Carpenter, is about a Nassau County police detective.

"It was like this was a real robbery," explained Garcia. "When they get there, they were confronted with a man with a gun. He put his arms up and said 'this is a movie,' but he still had the gun. An officer was able to get the gun out of the individual's hand."

Seven police cars and several unmarked cars responded to the scene.

"This could've gone very, very wrong." added Garcia. "If we did know, we could've had an officer there [on set]."

Garcia noted that the Nassau County Police have worked with Carpenter before while he films.

While charges were not filed against Carpenter or his crew, Garcia added that it is possible he might get billed for police time regarding this incident.