Considering that Ronda Rousey, the UFC's undefeated bantamweight champion, has proven she can kick anybody's ass in less than five minutes, no one in their right mind would want to piss her off.

But Justin Bieber, who was recently seen vacationing in Bora Bora with Ronda's long-standing rival Floyd Mayweather Jr., managed to get on Ronda's bad side at this year's Cannes Film festival. There, Ronda told Cosmopolitan.com during a UFC 193 promotional media tour, Justin snubbed her by refusing to take a photo with Ronda's 16-year-old sister Julia. Watch:

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When they approached Justin at an event, Ronda said, he straight-up refused to pose with them: "I've already taken a billion pictures today, OK?" he told Ronda. "A billion," he added before taking off.

It's hard to beliebe that Justin didn't recognize Ronda — after all, she swept this year's ESPY Awards, winning Best Female Athlete and beating Justin's buddy Floyd in the Best Fighter category.

Needless to say, crossing paths with Justin totally turned the fighter off: "I'm not a Belieber," Ronda told Cosmopolitan.com. "I was, but I'm not anymore."

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Elizabeth Narins Senior fitness and health editor Elizabeth Narins is a Brooklyn, NY-based writer and a former senior editor at Cosmopolitan.com , where she wrote about fitness, health, and more.

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