David Ian Hewlett (born 18 April 1968) is a British-born Canadian actor, writer, and director known for his role as Dr. Rodney McKay in the Stargate science-fiction franchise. He first gained fame for his roles as Grant Jansky in the Canadian TV series Traders (1996—2000) and as David Worth in the Canadian psychological horror film Cube (1997). He had earlier appeared in the horror film Pin (1988) and the science-fiction film Scanners II: The New Order (1991).