Bieber Fever: Singer Throws Up On Stage

Justin Bieber has apologised to fans after twice being sick on stage during a sell-out concert in America.

Video footage of the incident shows the international pop star vomiting in front of thousands of fans at an arena in Glendale, Arizona.

The first time he was performing Out Of Town Girl.

Later, as he was performing Beauty And A Beat, he ran off stage again and stopped the show abruptly for a few minutes.

He told the crowd "I'm sorry, I'm going to slow things down," and played the ballad "Fall" on an acoustic guitar.

"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?

"I wanted to give you my best show ever, so do you mind if I finish it?"

He later joked about his illness on Twitter.

He tweeted: "And .... Milk was a bad choice! Lol."

It is not the first time Bieber has been ill on stage.

The 18-year-old was so unwell during a Philippines concert in 2011 he had to take several backstage breaks.

At the time he was suffering from a chest infection but still performed for 90 minutes at the outdoor gig in Manila.