The world of showbusiness was in shock today at the news pop star Michael Jackson had died.

The singer died after suffering a suspected cardiac arrest, his brother said.

Jermaine Jackson said he believed the 50-year-old singer suffered the arrest at his Holmby Hills home in Los Angeles yesterday and was taken to the UCLA medical centre where he was pronounced dead.

Jackson's brother said: "My brother, the legendary King of Pop, passed away on Thursday June 25 at 2.26pm.

"We believe he suffered a cardiac arrest at his home, however the cause of his death is unknown until the results of the autopsy are known. The personal physician who was with him at the time attempted to resuscitated him."

The self-style King of Pop was due to perform 50 farewell concerts in London this summer, bowing out on an illustrious music career spanning several decades while aiming to restore his fortunes.

A spokesman for the hospital added: "When he arrived at hospital at approximately 1.14pm a team of doctors including emergency physicians and cardiologists attempted to resuscitate him for a period of more than one hour, they were unsuccessful."

TV footage showed a rescue helicopter flying the star's body to a waiting ambulance.

Tributes from the world of music, film and celebrity have flooded in.

His first wife Lisa Marie Presley told MTV: "This is such a massive loss on so many levels, words fail me."

Madonna said in a statement on the BBC website: "The world has lost one of its greats but his music will live on forever."

The head of the Sony Corporation Sir Howard Stringer said: "Michael Jackson was a brilliant troubadour for his generation, a genius whose music reflected the passion and creativity of an era."

And Justin Timberlake - who has been compared to a young Jackson - told MTV: "We have lost a genius and a true ambassador of not only pop music, but of all music."

A Los Angeles Police Department spokesman said the robbery and homicide team was investigating Jackson's death because of its "high profile". But he added nothing should be read into his team's involvement.

A post-mortem examination is expected to take place later today, Los Angeles Coroner's Office spokesman Fred Corral said.

Jackson's close friend Uri Geller told the Press Association it may have been the stress of Jackson's London comeback that killed him.

Speaking from his home in Sonning, Berkshire, he said: "I guess the stress, the anticipation and the passion he was emitting from his heart, wanting to do this comeback so badly, maybe that got to him.

"That is all I can think, that maybe the stress killed him."

He described Jackson, who was best man when Geller renewed his wedding vows, as a "genius".