AceShowbiz -

Justin Bieber lost his cool on a photographer outside of his London hotel, Friday morning, March 8. The Canadian popstar clashed with someone from the crowd of paparazzi when making his way to his awaiting car, dropping f-bombs and threatening the paparazzo.

It all started when Beiber pushed a shutterbug to give him some space, to which the photographer reacted, "That's assault." The singer's bodyguard quickly came to his defense, pointing out that the paparazzo got in their way. "I moved out the way," the shutterbug insisted.

The photographer didn't stop there as he dropped expletive insults at the 19-year-old star, "F**king little c***. That's assault. F**k back off to America. F**king little moron." At that point, Bieber was already inside his car but he apparently heard the insult and rushed out of the vehicle.

Wearing sagging pants, a red sweat shirt and matching beanie, a furious Bieber lunged at the photographer before being restrained by his bodyguard. "What the f**k did you say?" he screamed. "I'm gonna f**king beat the f**k out of you," to which his opponent continued to taunt him, "You heard what I said. Lose your f**king bouncers."

"Ahhhhh! Rough morning. Trying to feel better for this show tonight but let the paps get the best of me...," he later wrote on Twitter. "Sometimes when people r shoving cameras in your face all day and yelling the worst thing possible at u...well I'm human."

He went on, "Rough week. 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."

Bieber has been in U.K. for a while in relation to his "Believe" tour, but he didn't exactly have the best days lately. On March 1, he experienced a "worst birthday" after a party gone bad which he blamed on some "overly aggressive dummies."

A few days later, he faced backlashes from his fans and their parents for allegedly arriving two hours late to his first concert at the O2 Arena, which he claimed only 40-minute late and cited "technical issues" as the reason of the delay.

His problem continued on Thursday, March 7 when he had breathing difficulties on stage. He took a brief break to get treated by paramedics backstage before returning to the stage to finish the show. He later assured fans that he's "getting better."

He posted a photo of his shirtless self in a hospital bed, saying he listened to Janis Joplin. "Thanks for everyone pulling me thru tonight. best fans in the world. figuring out what happened. thanks for the love," he wrote.

After the dramatic episode, Bieber was back on stage Friday for his final concert in London. He will have the weekend off before he resumes his lengthy roadshow in Lisbon, Portugal on March 11.