Cox, a classically trained British stage actor, has a “turn it on, turn it off” approach to acting, and his relationship with Strong recalls a famous story about Laurence Olivier working with Dustin Hoffman on the 1976 film “Marathon Man.” On learning that Hoffman had stayed up partying for three nights before a scene in which he had to appear sleep-deprived, Olivier said, “My dear boy, why don’t you try acting?”