LOS ANGELES, California (CNN)  -- They poured in to Los Angeles from places far-flung, an army of Michael Jackson fans hoping to collectively mourn their idol in a massive ceremony at the Staples Center downtown Tuesday.



A fan leaves a note on a Michael Jackson memorial outside the Staples Center in Los Angeles.



The singer's memorial service Tuesday will be a star-studded affair, with singers Mariah Carey, Usher and Stevie Wonder among the participants, according to an announcement released on behalf of the Jackson family.



Also participating in the event will be basketball stars Kobe Bryant and Magic Johnson, and singers Jennifer Hudson, John Mayer and Smokey Robinson, the family said.



The Rev. Al Sharpton and Martin Luther King III will be among others taking part.



Ken Ehrlich, known for producing the Grammy Awards, is producing the memorial show, his company said. Kenny Ortega, who was to have co-directed Jackson's series of concerts in London, England, this summer, will direct it.



Mayer posted on Twitter on Monday afternoon saying "I'm going not to 'perform' but to contribute."



"I'm honored to have been asked to play at MJ's memorial service. I will be representing all of us who can't be there," Mayer tweeted. "Going to say goodbye from all us kids."



One notable who won't be attending: longtime Jackson friend Elizabeth Taylor, who put out a message on Twitter that she "cannot be part of the public whoopla."



"I just don't believe that Michael would want me to share my grief with millions of others," Taylor tweeted. "How I feel is between us. Not a public event."



"I love him too much," she added, "and I cannot guarantee that I would be coherent to say a word."



Debbie Rowe, Jackson's former wife and the mother of his two oldest children, will not attend the memorial service, her lawyer Marta Almli said Monday.



"Although Debbie had originally planned to attend tomorrow's Staples Center memorial service, we have concluded with Debbie that she will not be attending," a statement from Almli said. "The onslaught of media attention has made it clear her attendance would be an unnecessary distraction to an event that should focus exclusively on Michael's legacy. Debbie will continue to celebrate Michael's memory privately."



Fans without tickets to the memorial are being asked to stay away from downtown Los Angeles and watch the service on television.   Details: See who will be there, map of area »



The family decided to provide a free live video feed to networks so it would be televised everywhere. "Everything about the memorial has to do with accommodating as many fans as possible," Ken Sunshine, the Jackson family spokesman, said.



While Jackson's family remains tight-lipped about the singer's burial arrangements, sources told CNN that relatives will hold a private gathering at the Forest Lawn cemetery in Los Angeles Tuesday morning ahead of the public service. The California Highway Patrol will escort their motorcade, the sources said.



The gathering is scheduled for 8 a.m. (11 a.m. ET) -- two hours before the service at the Staples Center arena.



Cemetery officials have not commented on the matter.



While there are five Forest Lawn cemeteries in the Los Angeles area, media trucks and crews have been parked at the gate of the Hollywood Hills facility for several days in anticipation of Jackson's possible interment there.



Fans claim tickets



On Monday, fans chosen by random lottery for Jackson's memorial began arriving at Dodger Stadium in Los Angeles to pick up their tickets. Full story



Los Angeles Police Capt. Bill Murphy said the distribution process was going smoothly.



One person tried to pass off a photocopied voucher; he was ejected, Murphy said.



The 8,750 fans have until 6 p.m. PT to claim their tickets. iReport.com: "Surreal journey" to get Jackson tickets



Each winner gets two tickets, bringing the number awarded in the lottery to 17,500.
Whose memorial was Taylor and Rowe not attending? What is the relationship of Taylor and Rowe to Michael Jackson? who is not attending memorial Who are Jackson's former wifes? When is a private gathering expected to be held? When will the private gathering expected to be held at?
MJ's wife Elizabeth Taylor, Debbie Rowe, Tuesday morning ahead of the public service. the Staples Center downtown Tuesday.
question: Whose memorial was Taylor and Rowe not attending?, answer: MJ's | question: What is the relationship of Taylor and Rowe to Michael Jackson?, answer: wife | question: who is not attending memorial, answer: Elizabeth Taylor, | question: Who are Jackson's former wifes?, answer: Debbie Rowe, | question: When is a private gathering expected to be held?, answer: Tuesday morning ahead of the public service. | question: When will the private gathering expected to be held at?, answer: the Staples Center downtown Tuesday.