LOS ANGELES: Pop star Justin Bieber said he was leaving behind his "arrogant" and "conceited" attitude after bad behaviour in the past year damaged his image while he makes the transition from teen idol to adult performer.

The 20-year-old "Boyfriend" singer said in a video posted on his Facebook page late on Wednesday that he was "afraid of what people are thinking about me right now."

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Bieber's image was hurt by incidents involving careless driving, pelting a neighbour's home with eggs and an alleged assault following an altercation with a photographer.

"I didn't want to come off arrogant or conceited or basically how I've been acting in the past year, year and a half," the Canadian singer said. "I'm not who I was pretending to be."

Bieber has not had a U.S. top 10 hit since 2012 and last released a new music album in 2013. He has gotten more attention lately for his off-stage behaviour, including that of his entourage, than his music.

The singer said a nervous appearance on the Ellen DeGeneres television show earlier on Wednesday prompted his video.

His recent ad campaign for Calvin Klein underwear has been widely mocked and he will subject himself to a "roast" by comedians next month on U.S. television.

Bieber, who shot to prominence as a teenage heartthrob discovered on YouTube, called his behaviour a "cover up" of his emotional state.

"There was a lot of feelings going on in there, just being young and growing up in this business is hard, growing up in general is hard," he said.

The singer is currently serving two years' probation in Los Angeles after pleading no contest to a misdemeanour vandalism charge for throwing eggs at a neighbor's home a year ago.

The incident was the first in a string of legal problems for the former teen idol. He was arrested and charged with driving under the influence in Miami Beach in January 2014. He later pleaded guilty to a lesser charge of careless driving.

Bieber was also charged with assault and dangerous driving in Ontario, Canada, last August. The case is still pending.