The annual hip-hop summit Rock The Bells revealed its lineup on Wednesday (May 16), and while Nas, Kid Cudi and Wiz Khalifa top the 2012 bill, the big news is the promised special performance by Missy Elliott.

Elliott, who revealed her battle with Graves' disease last year and whose seventh studio album has been seven years in the making, will be making an "exclusive North American festival performance" at the festival series, which will invade San Bernardino, Calif. on Aug 18-19, Mountain View, Calif. on Aug. 25-26, and Holmdel, N.J. on Sept. 1-2. The rapper's longtime producer and collaborator, Timbaland, will join her for the performances.

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Meanwhile, Bone Thugs-N-Harmony will deliver a string of 20-year anniversary performances and run through their 1995 classic album E. 1999 Eternal in its entirety. RTB stalwarts Method Man and Redman will team up to perform their 1999 joint full-length Blackout! as well.

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Other notable performers at this year's festival include Chicago superstar Lupe Fiasco, 90s icons Salt-N-Pepa, Harlem heroes Dipset, and all four members of the Black Hippy squad -- Kendrick Lamar, Schoolboy Q, Ab-Soul and Jay Rock. The event will be hosted by RZA and Supernatural.

Ticket presages for this year's Rock The Bells events begin this Friday (May 18). Nas topped last year's RTB lineup, performing Illmatic in its entirety; Lauryn Hill, Erykah Badu and Black Star were also featured in 2011.