Season 1, Episode 2: Hot Lips Hannigan
Original Air Date: 7 October 1960
Fred is trying desperately to get an act for the "Amateur Night" at the Loyal Order of Dinosaurs. After failed attempts for a singing act, a trampoline act and a magic act, Fred and Barney made the girls disappear in a "Magic Box" and goes to a night club listening to an old school friend doing a music concert. What he does not know is that Betty and Wilma followed them disguised as "teenagers
i think they played a lot of switch..............but there is no proof perhaps