Justin Bieber isn’t MMA fight Ronda Rousey’s favorite person. In fact, she has a bone to pick with the “Where Have You Been?” singer.

In the November issue of Cosmopolitan, Rousey says her anger toward Justin Bieber stems from something that took place at the Cannes Film Festival this past spring.

“My little sister is really hard to impress and we really didn’t care about anybody that was at the Cannes Film Festival, but I wanted to spend some time with her,” she explains. “Justin Bieber was over there taking pictures with some ladies and she suddenly got really excited. She was like, ‘Do you think he would wanna take a picture with me?’”

Justin Bieber made Ronda Rousey's sister sad. You do not want to make Ronda's sister sad: http://t.co/p3QbiE6Dpd pic.twitter.com/r9Ku4VfzJg

— ESPN (@espn) October 7, 2015

Ronda Rousey assured 16-year-old Julie that yes, Justin Bieber would likely agree to take a picture with her. The two approached him, but he wasn’t willing to oblige.

“I’ve already taken a billion pictures today, OK? A billion,” Justin Bieber told Ronda Rousey.

Rousey said that before she could ask him again or plead on behalf of her sister, Justin turned and walked away.

“Yeah, I don’t think I’d wanna hang out with him,” Ronda Rousey says. “I’m not a Belieber. I was, but not anymore.”

Part of being a celebrity is appeasing fans. Justin Bieber should have either agreed to have taken a picture with Ronda Rousey’s sister, or had a publicist with him to tell fans when he was finished taking photos.

.@RondaRousey wants to beat the sh*t out of @justinbieber. http://t.co/FB1ld2XMBo pic.twitter.com/CdTzqflkRV

— Maxim (@MaximMag) October 8, 2015

Does Justin Bieber owe Ronda Rousey and her sister an apology?

The UFC’s undefeated bantamweight champion might not accept one if he offers it, however. Maybe she’d prefer to pound the arrogance out of the Biebs instead.

Can this uncomfortable situation between Justin Bieber and Ronda Rousey be worked out?