The R&B pop pair Milli Vanilli, a.k.a. Fab Morvan and Rob Pilatus, made lip-synching infamous in 1989. From Wikipedia: “The first public sign that the group was lip-synching came during a live performance on MTV … . As they performed onstage live in front of an audience, the recording of the song ‘Girl You Know It's True’ jammed and began to skip, repeating the partial line ‘Girl, you know it's...’ over and over on the speakers. They continued to pretend to sing and dance onstage for a few more moments, then they both ran offstage.”