WASHINGTON (AP) — Several stars are joining the lineup for the Earth Day celebration planned for April 20 on the National Mall in Washington.

Jordin Sparks from “American Idol, Black Eyed Peas frontman will.i.am, veteran rapper Doug E. Fresh, O.A.R. and others will join The Roots at the flagship event in Washington. Organizers say speakers will include Senate Majority Leader Harry Reid, NASA scientist James Hansen and others.

Simultaneous Earth Day festivals will also be held in New York, Chicago, Dallas, Denver, Los Angeles, Miami and San Francisco.

The events are being billed as the nation’s largest Earth Day celebration. Producers of the Green Apple Festival, which began three years ago in New York, and the Earth Day Network, a nonprofit created by the founders of the original Earth Day in 1970, are putting on the shows.

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