The 21-year-old singer, who has claimed he's curbed his wild antics, appears to have fallen back into his old ways after he was filmed swigging from a Cognac bottle and dousing the stage with the alcoholic beverage during his performance with Rae
Sremmurd at The Stage in Auckland.
Clearly amused by the clip, which was shot by a fan and uploaded online, Justin shared the video on his own Instagram account, admitting he was "drunk."
The What Do You Mean? hitmaker, who was arrested for driving under the influence (DUI) in Miami last year and tested positive for marijuana, allegedly later struck up a "joint" on stage, according to gossip website TMZ.com.
Friends of the star claimed his antics during the performance were part of a "dare" and he now regrets his behaviour.
According to his pal, the boozing on stage was a 'one off'.
Rapper Riff Raff believes the Where Are You Now? singer is still committed to cleaning up his act.
Riff told TMZ.com that he recently hung out with Justin, 21, and producer Diplo in Hollywood, where he is recording his new album, and Justin didn't smoke marijuana or drink any alcohol while he and Diplo were "fucked up".
He also claims the trio later went to a party and Justin remained sober the entire evening.
Riff Raff says his pal may have fallen off the wagon on the night, but thinks it was just a one off.