Justin Bieber
Justin Bieber lashes out at a paparazzi before being restrained by his own bodyguard.

Pop superstar Justin Bieber has been caught on camera threatening to beat up a photographer.

In the latest scandal to hit the teen sensation's UK tour, he was filmed lashing out at a paparazzi as he left his central London hotel. Bieber had to be restrained by his own bodyguard.

A video posted online shows the 19-year-old Canadian singer being hustled into a vehicle by his team after an argument with a waiting cameraman.

The unidentified pap shouts out that Bieber assaulted him and is heard insulting the Baby hitmaker, who was already inside his SUV, off camera.

He labels Selena Gomez's ex-boyfriend a "little moron" and tells him to go back to America.

Within seconds an angry Bieber bursts from the van, swearing, making threatening comments and lunging towards the photographer.

"What did you say? What did you say? I'll beat the f**k out of you," he shouts before security staff drag him back in the vehicle.

The star later addressed the altercation on Twitter, claiming he had been provoked.

"Trying to feel better for this show tonight but let the paps get the best of me..." he told his 34 million followers.

"Sometimes when people r shoving cameras in your face all day and yelling the worst thing possible at u ... well I'm human," he added. "Rough week."

He later added: "Not gonna let them get the best of me again. Gonna get focused on this show tonight. Adrenaline is high now. Gonna put it on the stage ... Only way someone can break u is if u let them."

Since arriving in the UK for his tour, Bieber has sparked concern among fans that he could be spiralling out of control.

He faced a backlash from fans and furious parents earlier this week after turning up late for his sold-out concert at London's O2.

The pop idol has also been snapped in the capital wearing a gas mask while out shopping and going bare-chested in freezing temperatures.

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