Pop star Justin Bieber has apologised for telling a racist joke that was caught on video.
The clip, obtained by editors at Britain's The Sun on Sunday newspaper, was shot during the production of his 2011 documentary Never Say Never.
In the short video, Bieber appears to ask pals, "Why are black people afraid of chainsaws?"
Grinning, Bieber then adds, "Run, n....., n....., n....., n....., run."
Bieber has since apologised, blaming the comments on his age.
"As a kid, I didn't understand the power of certain words and how they can hurt. I thought it was ok to repeat hurtful words and jokes, but didn't realise at the time that it wasn't funny and that in fact my actions were continuing the ignorance," Bieber has told TMZ.com.
Bieber goes on, "Thanks to friends and family I learned from my mistakes and grew up and apologised for those wrongs. Now that these mistakes from the past have become public I need to apologise again to all those I have offended.
"I'm very sorry. I take my friendships with people of all cultures very seriously and I apologise for offending or hurting anyone with my childish and inexcusable mistake. I was a kid then and I am a man now who knows my responsibility to the world and to not make that mistake again.
"Ignorance has no place in our society and I hope the sharing of my faults can prevent others from making the same mistake in the future. I thought long and hard about what I wanted to say but telling the truth is always what's right."
Bieber ends with: ""Five years ago I made a reckless and immature mistake and I'm grateful to those close to me who helped me learn those lessons as a young man. Once again....I'm sorry."
It is the latest blow to the singer, who counts prominent African Americans including Usher and rapper Lil Wayne among his celebrity friends, amid a storm of legal troubles.
Bieber, 20, will appear in court in July to face charges of DUI, resisting arrest without violence and driving with an expired licence following his arrest in Miami, Florida earlier this year.
He is also facing prosecution in Toronto, Canada, where he is accused of involvement in the alleged assault of a limousine driver during a night out in December.