He's no stranger to public bust ups himself and now Justin Bieber has spoken out about Conor McGregor's violent attack n New York on Thursday night.
Speaking to TMZ Sports, the singer said of McGregor, "I think Conor will be fine. We all make mistakes."
Bieber has followed McGregor's career for years and he publicly supported the controversial Dubliner when he fought Nate Diaz back in 2016.
McGregor was charged with assault after the incident which saw him and his entourage enter the Barclays Center in Brooklyn around 1.30pm (6.30pm Irish time) on Thursday and throw a trolley at a bus transporting fighters from a UFC 223 promotional event.
At least two people were injured when the bus window shattered, forcing them to withdraw from fights at this weekend's UFC 223 event.
McGregor has been released on bail of $50,000 after he was charged with assault, menacing and reckless endangerment following the incident.
The UFC champion appeared in court alongside fellow fighter Cian Cowley, who was released on a $25,000 bail for assault. Both men are due to appear in court again on 14 June.
Extended video footage has emerged of the incident.