Hundreds made a pilgrimage to the Jackson family's compound in Los Angeles, leaving flowers and messages of love. They did the same at his star on the Hollywood Walk of Fame and at the home in Los Angeles' Holmby Hills where Jackson was stricken. Some camped out overnight.

In New York, people stopped at Harlem's Apollo Theater, where Jackson had performed as a child with his brothers in one of rock's first bubblegum supergroups, the Jackson 5.

Scores of celebrities who knew or worked with Jackson — or were simply awed by him — issued statements of mourning. Some came through publicists and others through emotional postings on social networking sites like Twitter and Facebook, where countless everyday fans were sharing memories as well.

"I truly hope he is memorialized as the '83 moonwalking, MTV owning, mesmerizing, unstoppable, invincible Michael Jackson," said John Mayer. Miley Cyrus called him "my inspiration."

And Diana Ross, the former lead singer of the Supremes who introduced the Jackson 5 at their debut on "The Ed Sullivan Show" in 1969, said she could not stop crying. "I am unable to imagine this," she said. "My heart is hurting."

His two ex-wives both said they were devastated. One of them, Lisa Marie Presley, posted a long, emotional statement on her MySpace page in which she said her ex-husband had confided to her 14 years ago that he feared dying young and under tragic circumstances, just as her father, Elvis Presley, had.

"I promptly tried to deter him from the idea, at which point he just shrugged his shoulders and nodded almost matter of fact as if to let me know, he knew what he knew and that was kind of that," Presley said.

Presley's father, the King of Rock 'n' Roll to Jackson's King of Pop, died in 1977 at age 42 of a drug-related death.

At rehearsals for Sunday's Black Entertainment Awards show, stars like Beyonce, Wyclef Jean and Ne-Yo were frantically revamping their performances in an effort to turn the evening into a Michael Jackson tribute.

"There's a direct line from Ne-Yo to Michael Jackson," said executive producer Stephen Hill. "There's a direct line from Beyonce to Michael Jackson. There's a direct line from Jay-Z to Michael Jackson. I think they'll want to pay tribute in their own way."

When he was on trial on child molestation charges in 2005, Jackson appeared gaunt and had recurring back problems that he attributed to stress. His trial was interrupted several times by hospital visits, and Jackson once even appeared late to court dressed in his pajamas after an emergency room visit.

After his acquittal, Jackson's prosecutor argued against returning some items that had been seized from Neverland, the Santa Barbara County estate Jackson had converted into a children's playland. Among the items were syringes, the powerful painkiller Demerol and other prescription drugs.