Pop star Michael Jackson died Thursday following a cardiac arrest at his home in Los Angeles, officials said. He was 50.

The King of Pop, whose life of stardom and scandal kept him permanently in the headlines, was found unconscious at his rented Bel Air mansion and was rushed to the UCLA Medical Centre.

"We were notified by LAPD that Michael Jackson was transferred from his house to the hospital, " said Los Angeles County Coroner Fred Corral. "He was unresponsive and pronounced dead at approximately 2.26 this afternoon."

Corral said an autopsy would be performed to check for toxicology and other problems. The results are to be released Friday.

A large crowd formed outside the medical centre and his home, playing Jackson's music, as news crews and reporters jostled for stories and as news helicopters hovered overhead.

Corral said that he had suffered a cardiac arrest and local media reported Jackson had not been breathing when paramedics reached him. Reports from hospital first said he was in a coma, before numerous media reported his death.

"We are just stunned - I can't tell you what has taken place but everyone is just stunned, " family spokesman Brian Oxman told CNN. Referring to reports that Jackson was in ill health, Oxman said he "feared and warned about" the level of medication that Jackson was taking, though he stressed that "he was in fine condition. We have never seen him in any kind of weakened condition".

Jackson is survived by three children: Michael Joseph Jackson, Jr., Paris Michael Katherine Jackson and Prince "Blanket" Michael Jackson II.

Jackson had appeared increasingly frail and financially-challenged in recent years. Despite earning hundreds of millions of dollars he was reported to be $500 million in debt thanks largely to his eccentrically extravagant lifestyle.

Jackson's rented home was roped off after paramedics arrived to transport the King of Pop to the hospital.

Born in 1958 in Gary, Indiana, Jackson was a child star with the Jackson 5 and became one of the most successful recording artists of all time with the release of the album "Thriller" in 1982 - the best selling album of all time. His successful songs redefined the modern music video and forced MTV to start showing black performers, and paved the way for the acceptance of rap and hip-hop as mainstream musical styles.

Elevated to the stardom level of the Beatles and Elvis, he also introduced a new level of mega-stardom through his music and clothes, his dance moves, and his massive live concert tours.

"Michael Jackson made culture accept a person of colour - way before Tiger Woods, way before Oprah Winfrey, way before Barack Obama, " said black leader Al Sharpton. "Michael did with music what they did in sport politics and music. No controversy will erase his impact."

He raised consciousness about the plight of Africa with the supergroup recording "We Are the World" in 1985. But after that most of his headlines were dogged by scandal - from his marriages to Lisa Presley and former nurse Debby Rowe, to his eccentric lifestyle behind the gates of his fantasy childhood estate, named Neverland, after the setting of the book Peter Pan.

He managed to settle an allegation that he molested a boy there in 1993, but was forced to face a sensational "trial of the century" 10 years later. He was ultimately acquitted of the charges, but the exposure caused huge damage to his career and financial situation.

At the time of his death he had been preparing for a 50-concert run in London that was meant to represent his comeback and secure his financial future.