The Jackson 5 on The Sonny and Cher Comedy Hour, 1972

Watch Michael Jackson and The Jackson 5 (also Ronald Reagan, Howard Keel, Larry Storch, Wilfrid Hyde-White and series regulars like Teri Garr and Ted Zeigler (and maybe show writers Bob Einstein and Steve Martin too)) on the season three premiere of The Sonny and Cher Comedy Hour from 1972.
NB: guba.com, which had the full episode no longer exists and the video has been replaced with some of the available YouTube videos.