The Blue Boys

From "The Night They Raided Daddy's" episode (02/19/1970) of ABC TV sitcom That Girl.

They're hired to play Ann's father's restaurant, La Parisienne, to help boost business, which they do, but not for their music, but because they play in the nude.

Played by Gene R. Wallace (as Rayburn Wallace), Jeff Brock, and Joe Duckett.