Pop star Justin Bieber needed medical attention backstage at a gig in London after reportedly fainting during a concert on Thursday (07Mar13).

The singer's manager Scooter Braun took to the stage to tell worried fans Bieber was experiencing breathing problems, but he assured them he was going to be Ok.

Braun said, "The whole show he has been complaining. He's backstage with the Emts (emergency medical technicians) and the doctor. They're telling him that they want him to go and see someone and see what's going on with his lungs. He is telling me that in five minutes he's gonna come out and finish the show.

"He might not be jumping around as much... We're not trying to be disrespectful... we're truly trying to put on a show... Just bear with us... We're gonna do the best job to finish the show."

The manager's announcement was met with cheers and Bieber soon emerged to wrap the show.

A representative for the teen sensation confirms he was admitted to hospital for tests after the concert.

His latest health drama comes during a very trying seven days for the Baby hitmaker, who turned 19 last week (01Mar13). His London birthday party last Friday was marred by "overly aggressive dummies" and he faced the wrath of fans and their parents after taking to the stage at the O2 Arena in London late on Monday night (04Mar13).

Bieber's breathing troubles might help explain why the pop star has been hitting the streets of the British capital wearing a gas mask in recent days.