https://www.cnbc.com/2018/06/05/facebook-capitalizes-on-musical-ly-karaoke-trend-with-lip-sync-live.html

Facebook will allow users to sing along live to popular songs, following a popular teen trend popularized by apps like Musical.ly and Smule.

Lip Sync Live lets users try their hand at belting out top hits in real time using Facebook Live. The feature, which is being tested in a few markets, will also allow users to friends sing along with them using its "Live With" feature. Camera effects can be added the same as any Facebook Live video. Though the videos are streamed live, they can be posted and rewatched at a later date.