Workin' the Vamp
(Using the musical definition now)
Mavis Staples appeared on the Flip Wilson Show in 1972.
Listen as she slips into the repetitious groove of the music and comments on it throughout the song, I'll Take You There. (The video begins with a static, wallpaper image but opens into full video partway through the song. Hey, it was 1972. We didn't know any better.)