Los Angeles, Oct 1 (IANS): Teen sensation Justin Bieber has apologised to fans after he threw up on stage while performing.

He was performing in Glendale, Arizona, on the first stop of his Believe tour, Saturday night. He ran off the stage while dancers and a DJ continued to perform, before re-emerging and apologising to the audience.

"I am sorry, I am going to slow things down," digitalspy.co.uk quoted Bieber, 18, as saying.

He managed to complete "Karate Kid" theme song "Never say never" and his Nicki Minaj duet "Beauty and a Beat" before leaving the stage again.

"It's hard for me, you know, not feeling great and throwing up in front of a bunch of people," he told fans when he returned.

"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 said.

After the concert ended, the star took to Twitter to address what had happened.

"Great show. Getting better for tomorrow's show. Love u," he posted, along with a picture of himself lying in bed.

Bieber dedicated the show to a young fan who lost her battle with cancer last week.

"Goodnight Avalanna. Tonight was for you. I love you."