A worldwide chorus of grief united the famous - statesmen and superstars alike - and the legions of ordinary people who grew up with "Thriller" and "Beat It" following the death of pop legend Michal Jackson Thursday night. US President Barack Obama on Friday called the 50-year-old "King of Pop" a "spectacular performer" and a music icon, Reuters quoted White House spokesman Robert Gibbs as saying. According to the report, Gibbs also said Obama believed some aspects of Jackson's life were "sad and tragic" and offered his condolences to the musician's family. Jackson's death prompted broadcasters from Sydney to Seoul to interrupt morning programs, while fans remembered a "tortured genius" whose squeals and sliding moves captivated a generation and who sparked global trends in music, dance and fashion. Israeli television and radio stations spent much of Friday morning lamenting the singer and opened several consecutive broadcasts with news of his death. "It's horrible news, so unexpected," the Italian actress Sophia Loren told The Associated Press by telephone on Friday. "The world has lost an icon and music has lost treasures. He wrote songs that generations of yesterday, today and tomorrow will all keep on singing. What he wrote was amazing." Loren and her children had been frequent visitors to Jackson at his Neverland ranch in California, developing an enduring friendship. "I hope that Michael will find that peace that maybe he did not have in the last 15 years." Former South African President Nelson Mandela issued a message through his foundation saying Jackson's loss would be felt worldwide. Jackson sang at a birthday concert for Mandela in 1998, and in 1999, according to local media reports at the time, lunched with Mandela at a small gathering at which the South African anti-apartheid leader celebrated both his 81st birthday and his and wife Graca Machel's first wedding anniversary. Former Beatle Paul McCartney, who recorded with Jackson before they had a falling out over ownership of the Beatles catalogue, said his prayers went to Jackson's family and fans. "It's so sad and shocking," he said. "I feel privileged to have hung out and worked with Michael. He was a massively talented boy-man with a gentle soul. His music will be remembered forever and my memories of our time together will be happy ones." Former British child star Mark Lester, who is godfather to Jackson's children, said he had visited with Jackson several weeks ago and believed the star was ready for the rigors of performing 50 live gigs. "He was absolutely fine," said Lester. "I can't believe this, it's such a shock. I'll always remember him as being a very sweet, kind and loving man." Rocker Lenny Kravitz recalled working with Jackson in the studio on an unreleased track and finding the man far different from the eccentric recluse often portrayed in the media. "It was the most amazing experience I've had in the studio," Kravitz said. "He was funny. Very funny and we laughed the whole time. I also saw what a beautiful father he was. He was a beautiful human being. If not for him, I wouldn't be doing what I'm doing. He gave me joy as a child and showed me the way to go." Several world leaders weighed in. Venezuelan President Hugo Chavez called it "lamentable news," though he criticized the media for giving it so much attention. Former South Korean President Kim Dae-jung, who had met Jackson, said: "We lost a hero of the world."