From Hollywood a Go-Go:
Johnny Crawford (ex-The Rifleman, The Mickey Mouse Club) swapped his chaps and cowboy hat for a full time singing career after Rifleman ended. If memory serves, his first hit, "Cindy's Birthday", was released during his run as Mark McCain on Rifleman (1958-63).
In the winter of 1964-5, Johnny turned up on another series in the Four Star catalogue, the short-lived Hollywood a Go-Go, where he performs the David Gates-penned "The Girl Next Door". Host Sam Riddle does the intro: