We were watching an episode of The Carol Burnett Show that originally aired in 1975. The guest star was Shirley MacLaine.
There was an extended duet/production number. They started out with "Gorgeous," from The Apple Tree, but then, to my surprise, they morphed into "I Love to Dance," by Billy Goldenberg, which formed the backbone of his score for Ballroom. But that show didn't premiere on Broadway until 3 years later, in 1978.