From the movie Angels' Revenge AKA Angels' Brigade (1979). From a Charlie's Angels rip-off movie so bad it rightfully became an episode of Mystery Science Theater 3000. This disco diva is playing the Rainbow Room at the Sahara in Vegas. She gives a shout-out to audience member Arthur Godfrey (playing himself), who doesn't know why he's in this movie, either. When Wilson's drug addict brother gets beaten up by a pusher, Wilson is approached by a schoolteacher with a plan: use Wilson's star power to gather a group of commandos together to blow up the drug dealers' secret factory. Oh sure, that makes sense.
Trivia Time! Wilson's manager Manny is played Alan Hale, Jr., the Skipper from Gilligan's Island. There's also a role by his fellow castaway Jim Backus as a white supremicist!