Ontario's police watchdog says a sexual assault charge has been laid against a provincial police officer.

The Special Investigations Unit say their investigation started in August when a woman from Aurora, Ont., called in to make a complaint.

They say the alleged sexual assault happened in Aurora on August 9.

The unit says a provincial police constable will appear in court later this month in Newmarket, Ont.

The SIU is an arms-length agency that investigates incidents involving police that have resulted in death, serious injury or allegations of sexual assault.