Justin Bieber threw up on stage during a concert on Saturday (29.09.12).

The 'Boyfriend' singer was performing in Glendale, Arizona, as part of his 'Believe' tour, and while performing 'Out of Town Girl' he turned his back to the crowd and vomited.

He quickly exited the stage but returned and told the crowd he would like to continue the show.

Justin said: ''It's hard for me, you know, not feeling great and throwing up in front of a bunch of people. Will you love me even though I'm throwing up on stage? OK, I wanted to give you my best show ever, so do you mind if I finish it?''

Posting in a series of tweets on twitter after the concert he wrote: ''Great show. Getting better for tomorrow's show !!!! Love u. And ... Milk was a bad choice! Lol (sic)''

The Canadian pop star has been suffering from a mystery illness since the middle of last month, and tweeted before he began his tour that he was resting.

He wrote: ''All the travel and the body finally broke down. Soo sick. Just gonna chill. #nofun (sic)''