Justin Bieber I'm Sick but I'll Sing ... Not That You Asked

1/13/2017 6:51 AM PST

Justin Bieber Braves Bronchitis, Surprises Crowd with Mini Performance

Justin Bieber had every excuse to spit mucus, but instead went with lyrics.

The Biebs hit up Doheny Room Thursday night in WeHo and gave the crowd a surprise performance ... despite having bronchitis.

He's a pro.