Michael Jackson, the American pop legend, died of a heart attack in a Los Angeles hospital last night, just weeks before he hoped to resurrect his four-decade long career with a series of sold-out shows in London.

Jackson was taken to the University of California at Los Angeles medical centre last night, and paramedics administered cardiopulmonary resuscitation in the ambulance. He did not regain consciousness and was reported dead about three hours later.

Earlier his father, Joe Jackson, had told the TMZ.com website: "He is not doing well."

The site reported that a 911 call came in to emergency services at 12.21pm local time from his Holmby Hills home in Los Angeles. Once at the hospital, staff tried to resuscitate him but Jackson did not respond, the website said.

The website said his sister, La Toya, was seen running into the hospital sobbing.

Jackson's close friend Uri Geller told Sky News last night he was hoping desperately that the reports of Jackson's death were not true: "I must hear it from a doctor. I cannot believe everything I see and read and hear at the moment. I hope its not true, I'm waiting like you are, like the whole planet is waiting to hear it from the mouth of the doctor taking car of him.

"I'm absolutely devestated and shocked. He was a young man terribly fit and basically in good shape."

Last night fans paid tribute to Jackson. El Toro Diablo posted on TMZ: "God bless you Michael, heaven just got another beautiful angel."

Kimbers wrote: "What a sad day. I hope Michael Jackson finds the peace that eluded him in life."

Another fan, Sineen, wrote on website MJSite.com: "I never thought that one day would come and i'll have to write this down, Michael Jackson is no longer with us. May your warm soul rest in peace. I'll always love you Michael."

Rulintheroost posted on political website The Huffington Post: "RIP Michael. Your music was a joy to many people around the world."

The world famous entertainer had planned a series of 50 concerts in the O2 arena beginning 12 July. Although in the last two decades his reputation was sullied by accusations of child molestation and his bizarre public behaviour, 1m tickets were sold within hours, proving the King of Pop had enduring appeal, even among fans who were not yet born when he released the Thriller album in 1982.

Jackson's impact on American pop music cannot be overstated. His signature vocal style, dance moves and military-inspired fashion sense also influenced pop culture worldwide. He earned worldwide acclaim for his 1982 Thriller album, produced by Quincy Jones. His subsequent efforts, including his Bad album of 1987 and a collaboration with sister Janet, were also well received. His Thriller video, with its occult imagery and choreographed ensemble dance, helped launch the music video genre.

He ultimately sold more than 750m albums worldwide and won 13 Grammy awards. But he had withdrawn from the public eye, taking his last tour in 1997 and releasing his last album of new material in 2001. Raised in the Motown tradition, Jackson's worldwide popularity broke racial barriers.

For a time Jackson was the best-selling and most famous pop star in the world. But his increasingly odd public behaviour and two accusations of child molestation led the public to sour on him. The cost of his lavish lifestyle took a tremendous toll on his earnings. In 2008 he was forced to give up the deed to the Neverland Ranch in order to pay down what he owed. In April he stopped a public auction of his belongings including jewel encrusted concert tickets, stage-wear and music memorabilia. He was, at the time, thought to be as much as $24m in debt.

Jackson was born in Gary, Indiana, a gritty industrial city near Chicago. He became renowned in the 1970s as the lead singer of the Jackson 5, astonishing audiences with his charming looks, his crisp playful voice and his smooth dance moves. He broke through as a solo artist in 1979 with Off the Wall, produced by Quincy Jones. The two had a long and fruitful collaboration, producing the albums Thriller and Bad.

In 1993 Jackson was first accused of child molestation by a 13-year-old boy and his father. Authorities searched his ranch and Jackson agreed to a strip search. The case was eventually settled out of court and Jackson was never charged.

In 2003 he was the subject of a documentary by British filmmaker Martin Bashir, in which he admitted to sleeping in the same room as children at his Neverland Ranch. Prosecutors had been investigating him for years, and soon after, he faced new charges that he molested a 13-year-old cancer survivor. In 2005 a jury acquitted him of the charge.

Jackson married twice, the first time to Lisa Marie Presley, daughter of Elvis Presley, in an unusual union of pop music dynasties. He later married an Australian nurse and fathered two children with her. The mother of his third child is not known.

In recent years he has frequently been seen in public wearing a mask, as have his children. In 2002 he was seen dangling his infant from the balcony of a hotel room, as legions of photographers watched in horror below.

Jackson suffered from vitiligo, a condition that causes the skin to lose its pigment. In May the Sun reported he had been diagnosed with skin cancer, a rumour his camp denied.

Jackson had been engineering a comeback tour, an effort to rehabilitate his public image and bolster his tottering finances. The warp-speed sales of the tickets to his O2 shows indicated he is still beloved among his fans. A staggering 1m tickets sold out within a matter of hours after going on sale in March.