And to show you how early this performance is, it's not "Diana Ross and the Supremes." Just the plain ol' "The Supremes." In fact, Diana Ross doesn't get the center position. Florence Ballard does.
But then, it's pretty easy to figure out that this is early and vintage. After all, it's all three Andrews Sisters here -- Laverne, Maxene and Patty. (Laverne passed away in 1967.)
And making this all the more fun is the clever conceit of this "duet" -- the two groups don't challenge each other with whose songs are better...but they sing each others' songs! The Andrews Sisters sing The Supremes...and The Supremes sing The Andrews Sisters.
Not to worry -- at the end, they do finally join forces and all six sing together.
And just to toss one more feature into the mix, it's all hosted by Sammy Davis, Jr. From a bit of research, I think I've tracked down where this appearance is from. It appears to be a 1966 TV series, The Sammy Daivs Jr. Show which lasted seven episodes. The timing is most fortuitous since Laverne Andrews passed away only a year later.)