Pop star Justin Bieber posted picture of himself from his hospital bed and said he was "getting better listening to Janis Joplin".
Showbiz journalist Dan Wootton told Daybreak that pop star Justin Bieber is "under a huge amount of pressure."
Wootton said the singer has had to deal with a "huge backlash" this week for the first time in his career.
Earlier this week Bieber turned up two hours late for a gig at the London O2 Arena.
Wootton, who has spent time with the star on tour added, "I just think it was too much for him."
?@justinbieber: We hope you feel better Justin! Your health is the most important thing to all of us, we love you ? <333
OMG can't believe Justin is at the hospital!! get better <3 stay strong! all your beliebers are here for you! @justinbieber x
Pop sensation Justin Bieber is in hospital, after he fainted during his gig at the O2 Arena last night.
Bieber's manager Scooter Braun came on stage during the performance to explain what was going on.
One fan told Daybreak "we were worried about him," she said, "but at the same time I payed really good money, and I was really disappointed he didn't come out and play the whole set."
Justin Bieber left the stage of the O2 Arena mid-song, amateur footage shows. He is currently recovering in hospital.
Warning: This footage contains flashing images
Justin Bieber is recovering in hospital after he fainted during his gig at the O2 Arena last night.
He posted a picture of himself on Instagram from his hospital bed and said he was "getting better listening to Janis Joplin."
Singer Justin Bieber was rushed off stage at the O2 during his concert, after apparently suffering from breathing problems.
In a Twitter post the Canadian pop sensation said he was "getting better."
getting better. thanks for everyone pulling me thru tonight. best fans in the world. figuring out what happened. thanks for the love
Canadian teen pop star Justin Bieber collapsed on stage from shortness of breath during his performance at the O2 Arena last night, representatives for the singer said. Bieber's spokeswoman Melissa Victor said:
Justin's heading to the doctor now. He fainted and took a 20-minute reprieve and was given oxygen.
Bieber was performing for the third out of four nights at London's O2 Arena as part of the European leg of his sold-out "Believe" world tour.
We're at Justin Bieber's London O2 show and he's just been taken off stage to be checked over by doctors. Agh!
Canadian pop sensation Justin Bieber rushed off stage at the O2 during his concert this evening, after apparently suffering from breathing problems.
His manager Scooter Braun came on shortly after he left the stage to explain what was happening to his thousands of worried fans, many of whom had taken to Twitter to report the star had "collapsed."
His manager said his doctors backstage asked him not to continue the show, but he insisted, and returned to the stage, much to the relief of his fans.