Pop star Michael Jackson has died in Los Angeles, aged 50.
Paramedics were called to the singer's Beverly Hills home at about midday on Thursday after he stopped breathing.
He was pronounced dead two hours later at the UCLA medical centre. Jackson's brother, Jermaine, said he was believed to have suffered a cardiac arrest.
Jackson, who had a history of health problems, had been due to stage a series of comeback concerts in the UK, beginning on 13 July.
Speaking on behalf of the Jackson family, Jermaine said doctors had tried to resuscitate the star for more than an hour without success.
Jermaine Jackson on his brother's sudden death
He added: "The family request that the media please respect our privacy during this tough time."
"And Allah be with you Michael always. I love you."
TV footage showed the star's body flown from UCLA to the LA County Coroner's office where a post-mortem is expected to take place on Friday.
Concerns were raised last month when four of Jackson's planned comeback concerts were postponed, but organisers insisted the dates had been moved due to the complexity of staging the show.
Michael Jackson was brought here to the UCLA Medical Center in Los Angeles around 12 hours ago. Earlier there were several hundred people here, before it got dark - there was a sense of grief, of disbelief.
But in the last few hours, these people have been singing his songs, dancing, there was a guy on a keyboard earlier, playing his songs for people to dance along to.
This has turned into an impromptu celebration of Michael Jackson's music. He's the king of pop as far as they're concerned. They're still shocked by his sudden death but they're here because they want to show their support.
A spokeswoman for The Outside Organisation, which was organising the publicity for the shows, said she had no comment at this time.
Broadcaster Paul Gambaccini said: "I always doubted that he would have been able to go through that schedule, those concerts. It seemed to be too much of a demand on the unhealthy body of a 50 year old.
"I'm wondering that, as we find out details of his death, if perhaps the stress of preparing for those dates was a factor in his collapse.
"It was wishful thinking that at this stage of his life he could be Michael Jackson again."
Uri Geller, a close friend of the star, told BBC News it was "very, very sad".
Speaking outside New York's historic Apollo theatre, civil rights activist Rev Al Sharpton paid tribute to his friend.
"I knew him 35 years. When he had problems he would call me," he said.
(CREDIT: Thanks to BBC News for this story).
