There was a "B-movie" called Hootenanny Hoot produced during this period (i.e., a quickie film slapped together in a rush, in order to exploit a current pop-culture trend). Featured performers included Judy Henske, The Brothers Four, Shep Wooley, Johnny Cash, Joe and Eddie, and a few others I'm failing to remember. (Joe and Eddie, who I had completely forgotten, were excellent ~ it seemed to me that their performance held up over the years much better than anyone else's in the film.)
The plot was ridiculous, of course, and the "lead" actors are all now-long-forgotten nobodies, but the muical performances ~ most of them anyway ~ make the film worth a look.
I saw it on Turner Classic Movies several months ago (maybe as long as a year ago), so we can be fairly sure it'll pop up again on that channel sooner or later. There is some info on the internet ~ copies may be available for sale, but I know that it is not available for rental from Netflix.
There's another, older, Mudcat thread where this film is mentioned and discussed.