Police in the US say they're investigating after an officer in the western Indiana city of Crawfordsville fired a gunshot at a movie actor portraying a bank robber.

State police say Crawfordsville officers were responding to a report of a possible robbery at Backstep Brewing Co. on Tuesday evening when they encountered actor Jim Duff.

Mr Duff was wearing a ski mask and carrying a gun while leaving the brewery with his back to the officers.

Police told him to drop the gun, but Mr Duff turned toward them.

An officer then fired a shot that missed him.

Police said Mr Duff dropped the gun, pulled off his mask and told officers they were on a movie set.

Police said the production company and the brewery didn't notify them or other businesses before filming.