Pop’s top sirens sing for charity

What would it sound like if 15 of the hottest female singers joined voices? The answer will be revealed Sept. 2.

That’s when “Just Stand Up” hits airwaves and iTunes. The song features Mariah Carey, Beyonce, Mary J. Blige, Rihanna, Fergie, Sheryl Crow, Miley Cyrus, Melissa Etheridge, Ashanti, Natasha Bedingfield, Keyshia Cole, Ciara, Leona Lewis, LeAnn Rimes and Carrie Underwood.

The charity tune was conceived by Antonio “L.A.” Reid, who produced it with longtime creative colleague Kenny “Babyface” Edmonds. All sales of the single will benefit cancer research.

All 15 singers will share the stage to perform the song live on Sept. 5 during the “Stand Up to Cancer” television special, set to air simultaneously on ABC, NBC and CBS.