Justin Bieber upsets Ronda Rousey by dissing her sister

Justin Bieber has picked a fight he may want to avoid after upsetting undefeated Ultimate Fighting Championship tough girl Ronda Rousey.

The Furious 7 bada** claims the Baby singer was rude to her teenage sister when she asked him for a photograph at the Cannes Film Festival in France earlier this year (May15).

Rousey tells Cosmopolitan, "I wanted to spend some time with her (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?'"

The UFC star was hoping to make the 16 year old's dreams come true and approached the pop superstar.

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

Rousey reveals the encounter left her sister in tears and told her big sister she was "no longer a Belieber".