Michael Jackson died after suffering a cardiac arrest, officials confirmed, sending shockwaves around the entertainment world as stunned stars and fans mourned the loss of the tortured music icon known as the "King of Pop." Los Angeles County Coroner's office spokesman Lieutenant Fred Corral told CNN that Jackson, 50, was pronounced dead at 2:26 pm (2126 GMT) local time, roughly two hours after paramedics were first called to the star's home. "I can tell you at this time that we were notified by West Los Angeles Police Department detectives that Mr Jackson was transported... to the hospital, and upon admitting, he was unresponsive and was pronounced dead at approximately 2:26 this afternoon," Corral told CNN. Corral said an autopsy would "most likely" be carried out on Friday but would not speculate on the exact cause of death. "Everything is still ongoing. We will be responding to the hospital to move Mr Jackson to our facility where he will be examined to determine the cause of death," Corral said. "As far as I'm aware, we were notified by LAPD detectives that Mr Jackson was brought in by paramedics to the hospital in full cardiac arrest and then he was later pronounced dead. National and local television networks showed hundreds of media and onlookers gathered at UCLA Medical Center, while CNN showed police motorcycle riders surrounding Jackson's rented mansion as crowds of tourists and fans gathered, snapping photographs of the property's wrought iron gates. Lana Brown, a 49-year-old tourist from Dallas, broke down in tears as she digested the news. "Right today I can't believe we might have lost the best entertainer this world has ever seen," she told AFP. CNN reported that several of Jackson's siblings had gathered at the hospital. Jackson's death came as the singer prepared to make a keenly anticipated concert comeback in London, his first series of shows in more than a decade and the first since his 2005 acquittal on child molestation charges. However those concerts -- billed as the "final curtain" -- were thrown into doubt after Jackson pushed back the opening dates last month. Organizers of the concerts at the time stressed the delay was not linked to Jackson's health. When asked about Jackson's physical condition, Randy Phillips of concert backers AEG Live said: "I would trade my body for his tomorrow. He's in fantastic shape." While Jackson reigned as the "King of Pop" in the 1980s, his once-stellar career was overshadowed by his colorful public behavior, his startling physical transformation and multiple allegations of child abuse. Jackson lived as a virtual recluse following his 2005 acquittal on charges including child molestation and plotting to kidnap his young accuser. Despite his acquittal, the trial was a body blow from which the pop music superstar struggled to recover. Four years later, Jackson was still worshipped by fans for revolutionizing music, dance and music videos at the peak of his success. The attention however paid to him in recent years was less flattering, focusing on apparent cosmetic surgery -- which he denies -- his baby dangling antics and a decade of swirling child abuse allegations. Born on August 29, 1958, Jackson made his show business debut with four of his older brothers in the Jackson Five pop group, and went on to lead the stage clan with a piping soprano and dazzling dance moves. By 1969, the group had signed a contract with Motown Records, becoming one of the last great acts to emerge from the legendary label. The Jacksons produced seven platinum singles for Motown, selling over a million, and three multi-platinum albums, selling more than two million. They moved to CBS's Epic Records in 1976. Despite the early success, Jackson was to recall those years as unhappy and lonely ones. Eventually the family act broke up, as Jackson went solo. In 1979, Quincy Jones produced Jackson's first solo album for Epic, "Off the Wall," a huge disco-oriented success that sold 10 million copies. They teamed up again in 1982 for what would be Jackson's breakthrough album as a composer and co-producer, "Thriller," which became the top-selling album of all time, with sales exceeding 41 million. Jones reacted with shock after being informed of Jackson's death Thursday. "I'm absolutely devastated at this news," he said. "I just don't have the words. Divinity brought our souls together and allowed us to do what we could do through the '80s," Jones said. "To this day that music is played in every corner of the world, and the reason is because he had it all -- talent, grace, and professionalism. I've lost my little brother today and part of my soul has gone with him."