Canadian pop star Justin Bieber returned to the stage Friday after a torrid 24 hours in which he suffered a health scare then lashed out at a photographer.
The 19-year-old said he had had a "rough week" and was "human" following the foul-mouthed confrontation with a paparazzi cameraman in London.
Bieber was forced to halt a London show for 20 minutes on Thursday night after complaining of being "light of breath" and was later taken to hospital.
The teen idol was back on stage Friday night for the last of four shows at London's O2 Arena -- having angered British fans with a very late start in the first show on Monday.
"Sometimes when people r shoving cameras in your face all day and yelling the worst thing possible at u...well I'm human. Rough week," Bieber wrote on Twitter ahead of Friday's show.
"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."
Footage of the incident broadcast on Britain's Channel 5 News showed Bieber apparently making contact with the unnamed member of the paparazzi as minders rushed the star into a van outside his central London hotel.
The unnamed cameraman shouted swear words at Bieber -- who was dressed in a red sweatshirt and beanie -- and told the Canadian star to "go back to America".
Bieber got out of the van and said "What did you say?" to the photographer before unleashing a series of swear words and threatening to "beat the fuck out of you".
The star's security team then bundled him back into the van before it drove off.
The performer's later apologies came on his Twitter account, which is the world's most popular with 35.6 million followers.
Bieber has a history of run-ins with paparazzi. In May he allegedly kicked and punched a photographer in a parking lot in the United States but no charges were filed.
In January he offered prayers -- while calling for tougher laws against paparazzi -- after a photographer was killed on a freeway while trying to get a picture of Bieber's Ferrari. The singer was not in the car at the time.
Bieber's stay in London started badly when his show on Monday began two hours late. He blamed the tardy showtime on technical difficulties.
On Thursday he walked off mid-way through a song towards the end of his set Thursday and a spokeswoman said then that he was "feeling a little under the weather".
His manager Scooter Braun told the 20,000-strong crowd that the singer was determined to return to the stage against medical advice.
"Justin got very light of breath, the whole show he's been complaining. He's backstage with the EMTs (emergency medical team) and the doctor," Braun said.
His representative told entertainment channel E! News that emergency personnel gave him oxygen.