The lineup for the Oct. 21 United We Stand -- What More Can I Give? concert has grown by three, as R&B/pop acts Mariah Carey, Destiny's Child, and Usher have all signed on for the Oct. 21 concert

The lineup for the Oct. 21 United We Stand -- What More Can I Give? concert has grown by three, as R&B/pop acts Mariah Carey, Destiny's Child, and Usher have all signed on for the Oct. 21 concert in Washington, D.C. The trio of artists join previously announced acts Michael Jackson, 'N Sync, Aerosmith, the Backstreet Boys, Rod Stewart, Ricky Martin, Train, P. Diddy, Goo Goo Dolls, James Brown, and Al Green for the event, to be held at RFK Stadium. More artists will be announced in the days leading up to the concert.

Tickets for the event went on sale today (Oct. 12), and are nearly sold-out, according to a statement from organizers. Proceeds will benefit the American Red Cross Liberty Relief Fund, the Salvation Army Relief Fund, and the Pentagon Relief Fund.

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