It was clear from an early age that Rubinek had been bitten by the acting bug. He was encouraged by his parents, who took him to acting classes and allowed him to perform regularly at the Ottawa Little Theatre. Four years later, in 1969, he joined the company at the STRATFORD FESTIVAL in Ontario.
Thompson met Mark MCKINNEY while performing with a sketch comedy troupe called The Love Cats. McKinney was already working with Bruce MCCULLOCH in the comedy duo The Audience. They later teamed up with Dave FOLEY and Kevin McDonald, who were working under the name THE KIDS IN THE HALL.