Mariah, Beyonce, Rihanna and Others Release Cancer Benefit Single

Some of the biggest female singers on the planet have gotten together to record vocals for a star-studded single called "Just Stand Up," benefiting the Stand Up to Cancer campaign. The unprecedented gathering features vocals from Mariah Carey, Beyoncé, 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 tune is being produced by the powerhouse duo of Kenny "Babyface" Edmonds and Antonio "L.A." Reid, who are working together for the first time in nearly 20 years on the track.

The song will be available for purchase exclusively on iTunes on September 2 and will get its TV premiere on September 5 during the live "Just Stand Up" special, which will air simultaneously and commercial-free on CBS, ABC and NBC. According to a press release announcing the project, the song was conceived by Reid, the chairman of the Island Def Jam Music Group, after a meeting with the women behind the Stand Up to Cancer campaign.

Among the stars confirmed to either appear or answer phones on the TV broadcast so far are: Casey Affleck, Jennifer Aniston, Christina Applegate, Lance Armstrong, Abigail Breslin, Josh Brolin, David Cook, Dana Delany, Fran Drescher, Julia Louis-Dreyfus, Kirsten Dunst, Elizabeth Edwards, Jon Favreau, America Ferrera, Neil Patrick Harris, Salma Hayek, Scarlett Johansson, Masi Oka, Danica Patrick, Christina Ricci, Robin Roberts, Homer Simpson, Marge Simpson, Meryl Streep, Hilary Swank, Charlize Theron, Goran Visnjic, Forest Whitaker and Reese Witherspoon.

"Samantha Who?" star Christina Applegate, 36, is free of cancer after having both breasts removed to combat the disease, the actress told a U.S. television news show on Tuesday.

Applegate, who revealed her diagnosis for breast cancer earlier this month, had the double mastectomy performed a month after her diagnosis, she said on ABC's "Good Morning America."

The actress, who stars on the ABC sitcom "Samantha Who?," said she bore a genetic risk for developing breast cancer, and she said her surgery was meant to prevent the cancer she suffered in one breast from coming back. But she said it was difficult to have both breasts surgically removed.

Applegate told "Good Morning America" she is starting a charitable foundation to help women meet the costs of MRI exams, which is how her disease was discovered.

The actress also will appear on upcoming TV fundraiser "Stand Up to Cancer" singing alongside Mariah Carey, Beyonce and Sheryl Crow, who also has battled breast cancer.