Photo: Ferdaus Shamim/WireImage.com

Two decades after Annie Lennox first sang "Sisters Are Doin' It for Themselves," she's still taking her own advice. For her rousing, gospel-like new single, "Sing," she's gathered 23 of the world's top female vocalists, including Madonna, Shakira, Celine Dion, Fergie, and Faith Hill, to join her in another call for women's empowerment—this time in support of those affected by the HIV/AIDS pandemic in Africa.

The recording is an outgrowth of Lennox's involvement with South Africa's Treatment Action Campaign (TAC), an HIV/AIDS prevention and treatment advocacy organization. The original version of "Sing" appears on Lennox's new album, Songs of Mass Destruction, but in honor of World AIDS Day on December 1, she is releasing a series of remixes of the song online (AnnieLennoxSing.com). All profits will support TAC's health initiatives, including a countrywide effort to prevent mother-to-child HIV transmission.