- Green Growth
- Your Consultant
But the singer assured fans a few hours later on twitter that he's "getting better".
Bieber was reportedly given oxygen by doctors backstage and managed to return 20 minutes later to perform because he "insisted on finishing the show".
In a video posted by a fan on YouTube, Bieber's manager Scooter Braun tells the crowd: "Justin got very light of breath, the whole show he's been complaining."
The Canadian singer was performing his hit song "Beauty and the Beat" when he fainted.
Right after the concert at London's O2 arena, Bieber was rushed to a hospital to be checked out.
Three hours later, Bieber said on twitter that he's "getting better" and thanks fans for their love and concern.
Shortly after the news of his collapse, worried fans started trending the hashtag #JustinTakeABreak on twitter to tell the superstar to "take a vacation" and "just get back to full health".