Justin Bieber Performs with Don Toliver, Hailey Bieber Dances and Cheers

Justin Bieber getting back onstage ... performing alongside pal Don Toliver -- all while his wife Hailey supported him from the crowd.

The pop star took the stage during DT's L.A. show Saturday night ... singing and dancing. There were some cheers in the crowd, and lots of cameras filming the star who doesn't perform nearly as much as he used to.

Videos posted to IG by Hailey also capture her reaction to her man gettin' back onstage ... dancing to Toliver's tracks while seated pretty far from the stage in what appears to be some sort of VIP area.

Just Hailey and Justin at the event as far as we can tell ... their two-month-old son Jack didn't appear to got the loud, crowded concert with mom and dad.

Justin posted about the new addition to their family soon after they brought him home ... taking a picture of his tiny foot and captioning it "WELCOME HOME."

JB and HB have been spending a decent amount of time at home as far as we can tell ... and, Justin doesn't really perform much anymore anyway since he had to quit touring after his Ramsay Hunt syndrome diagnosis.