On stage, he played the part of Lycus in the 1963 London production of "A Funny Thing Happened on the Way to the Forum" with Frankie Howerd and appeared in the smaller role of Crassus in the 1966 film version. He appeared as Sidney Tait in the comedy film "Ladies Who Do" (1963). In 1966, Pertwee starred alongside Donald Sinden in the original West End production of the long-running comedy "There's a Girl in My Soup" and in this period appeared in several "Carry On" films: "Carry On Cleo" (1964), as the soothsayer; "Carry On Cowboy" (1965) as Sheriff Earp; and "Carry On Screaming!" (1966) as Dr. Fettle. ("Carry On Columbus", with Pertwee in his fourth "Carry On" role, this time as the Duke of Costa Brava, was released in 1992). In 1967, he was chosen by "Dad's Army" producer David Croft for the role of Captain George Mainwaring, but Pertwee turned it down – possibly because he preferred to extend his role on Broadway in "There's a Girl in My Soup".