Ronda Rousey has serious beef with Justin Bieber

Oct 8, 2015 at 9:45 p.m. ET

More bad news for the Biebs.

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Just a day after a privacy-invading paparazzo splashed his genitals all over the 'net, 21-year-old singer Justin Bieber is making headlines again — by making a very scary enemy.

People magazine reports that there's a feud brewing between Bieber and the one person we know we'd never want to fight: undefeated UFC Women's Bantamweight champion Ronda Rousey.

But by the sound of Rousey's story, the Biebs had it coming. She claims the "What Do You Mean?" singer dissed her little sister, Julia De Mars, by refusing to pose for a photo at this year's Cannes Film Festival.

"I wanted to spend some time with [Julia], and Justin Bieber was over there taking pictures with some ladies and she suddenly got really excited and she was like 'Do you think he'd want to take a picture with me?'" Rousey shared.

She added that she called Bieber a "sweetheart" as she told her little sis a photo would be no problem and then approached him to ask about it.

"I walked over there and I said, 'Excuse me,' and he said 'I've already taken a billion pictures today,'" Rousey said. "And I said 'Yeah, but' — because she was the only 16-year-old girl at the whole party — and I only got 'Yeah, but' out, and he goes 'A billion' and walks off.'"

Bad call, Biebs. We're willing to bet Rousey could crush him. Blindfolded. With one hand behind her back. Hell, with both hands behind her back.

Rousey said her sis was fighting back tears after the incident, proclaiming she was "no longer a Belieber." Rousey agreed and said she is also "not a Belieber anymore." And we can't blame them.

People reports that Bieber's camp hasn't responded to requests for comment about the incident.

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Do you think Justin Bieber was way too rude to Ronda Rousey's sister? Or were his actions justifiable? Head down to the comments and let us know what you think.