Is Justin Bieber an aspiring boxer? This weekend he made a shocking appearance as he joined Floyd Mayweather's entourage into the boxing ring - even holding his belt along with rapper 50 cent.

And now there are reports that he has been punching other band-mates around. Bieber reportedly punched The Wanted's member Siva Kaneswaran in the groin twice. The incident apparently occurred backstage at "The Voice" in Los Angeles, when the band performed their new single "Chasing the Sun". Bieber also made an appearance on the show.

The Wanted's Jay McGuiness told British publication The Mirror : "Justin Bieber is a prankster.

"He pranks people all day. Although I'm not actually sure that what he did to Siva was a prank...We'd done the show and Justin basically just came up and punched Siva hard in the balls. And then did it again. Siva wanted to hit him back, but you can't go around smacking kids... he's only little."

Tom Parker, another member of The Wanted, added: "Siva limped into the dressing room and asked 'Why's he picking on me?' It was funny."

Kaneswaran appeared on UK's Daybreak and confirmed the fact that Justin punched him in the privates. "He came up to me during a conversation and smacked me in the privates," he said. It was a game, a very aggressive game, which was very painful!" The poor guy joked that he will take revenge on Bieber, saying: "Who'd win in a fight, me or Bieber? Exactly. But you cannot go around hitting children. And anyway, he's got million-dollar sperm... I couldn't possibly go there. But I'll get him back..."

Last month, The Wanted said they planned on a duet with Justin Bieber and Chris Brown. McGuinness told MTV: "He [Justin] was really nice. A really, really nice guy. We talked about it, and we have a song that we think he'd sound great on."

See Now: Famous Actors Who Turned Down Iconic Movie Roles