With just hours to go before the [article id="1615380"]Michael Jackson memorial service[/article] packs the Staples Center, a source close to the event told MTV News that even more big-name artists have signed on to pay tribute to the King of Pop.

[artist id="1231683"]Justin Timberlake[/artist], [artist id="7590"]Jamie Foxx[/artist] and [artist id="1198"]Queen Latifah[/artist] will all appear at Tuesday's (July 7) memorial service, joining a previously announced [article id="1615358"]list of Jackson's closest friends, collaborators and mentors[/article], including [artist id="976"]Mariah Carey[/artist], [artist id="2481017"]Jennifer Hudson[/artist], [artist id="1270"]Usher[/artist], [artist id="19226"]Stevie Wonder[/artist], [artist id="15109"]Lionel Richie[/artist], Motown founder Berry Gordy and [artist id="1220799"]John Mayer[/artist].

Usher, Mariah, More To Appear At MJ Memorial

Other confirmed participants in the memorial service include a pair of Los Angeles Lakers' greats -- Kobe Bryant and Magic Johnson -- Motown legend Smokey Robinson, Jackson family friend the Reverend Al Sharpton, "Britain's Got Talent" finalist Shaheen Jafargholi (who toured as a young MJ in the "Thriller Live" show), Martin Luther King III and Jackson's longtime pal, actress Brooke Shields.

At press time, who will be performing at the service was unconfirmed. Some reports have Carey reprising her version of the Jackson 5's "I'll Be There," photographs have emerged online of Wonder and Usher apparently rehearsing for memorial performances; Jackson family spokesperson Ken Sunshine told ABC that Latifah would perform as well. According to a statement released by the family, no further information will be released regarding the program before the service.

Though she will not appear at the Staples Center, [article id="1615279"]Madonna recently paid tribute to Jackson[/article] during a show at London's O2 Arena -- the same venue where Jackson's 50-show run was slated to kick off next week -- with one of her dancers interpreting some of MJ's famous dance moves to a medley of "Billie Jean" and "Wanna Be Startin' Something."

In Jackson's hometown of Gary, Indiana, Mayor Rudy Clay has announced that another Gary-born singer, Deniece Williams -- who sang "Let's Hear It for the Boy" from the soundtrack to the 1984 film "Footloose" -- would be among the performers at a Friday memorial service at the U.S. Steel Yard baseball stadium, according to the Gary Post-Tribune. A 500-member choir will also sing "We Are the World" at the service.

MTV's live coverage of the Michael Jackson public memorial service at the Staples Center in Los Angeles will begin on Tuesday at 12 p.m. ET / 9 a.m. PT.

For complete coverage of the life, career and passing of the legendary entertainer, visit "Michael Jackson Remembered."

Share your Michael Jackson memories by uploading video and comments to Your.MTV.com or joining the discussion below.