Justin Bieber reportedly guzzled down brandy and smoked marijuana during a gig in New Zealand last night (01.10.15).

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.

Meanwhile, Justin - who has had a number of run-ins with the law in recent years - believes as he's grown older he's changed and he's no longer interested in ''rebelling.''

He said recently: ''I came into the music industry at 13. I was trying to trust people and they'd break my heart at 15. You have your perceptions of people. There are awesome people who are the lovely, amazing, joyful kind.''

He added: ''But I only saw people who are s****y and were taking advantage of me. When you have that perspective, the way you act changes. I was basically like, F**k everybody. Then I started doing my own thing. I got into a little bit of trouble -nothing that other 20 year olds don't get into - just rebelling a little bit.

''Now, being 21, I'm coming into my own and around some pretty cool people who are not afraid to tell me what's real.''