Two months prior to his tribute concert, Michael Jackson has disclosed a list of guests scheduled to appear at his Michael Jackson: 30th Anniversary Celebration, The Solo Years show. According to SonicNet.com, Gloria Estefan, Luther Vandross, Diana Ross, Missy Elliot, Ramsey Lewis, Lil' Romeo, Gloria Gaynor, Jill Scott, Mary J. Blige, Ricky Martin and Usher have been included to the previously announced Sept, 7 and 10 concerts in New York's Madison Square Garden. They will join a cast that already includes 'N Sync, Marc Anthony, Britney Spears, Whitney Houston, Mya, Shaggy, and the rest of Jackson 5. This will be the first time that the King of Pop will perform in the United States in 11 years. His album Invincible is scheduled for release on Epic Records on Sept. 25.