The competition among TV networks, movie studios and A-list stars can be fierce, but the fight against cancer will unite them on Sept. 5.
More than 60 celebrities will participate in Stand Up to Cancer, a live fund- and awareness-raising television special that will air simultaneously on ABC, NBC and CBS.
Jessica Alba, Halle Berry, Jack Black, Sheryl Crow, Ellen DeGeneres, Jennifer Garner, Diane Keaton, Rob Lowe, Sharon Osbourne, Keanu Reeves and Carrie Underwood are among the stars set to appear, it was announced Wednesday.
They'll join previously announced participants including Salma Hayek, Scarlett Johansson, Lance Armstrong, America Ferrera, Meryl Streep, Charlize Theron and Forest Whitaker.
The celebrities, along with network news anchors Katie Couric, Charles Gibson and Brian Williams, will deliver an evening of "edutainment," said executive producer Laura Ziskin, a cancer survivor who helped establish the event and the nonprofit group behind it.
"There will be laughter. There will be tears. And you'll learn something about how we can turn the outcome of this disease if we just set our minds to it," Ziskin said.
Ziskin described the special as "a phone-in, a sit-in, a love-in."
"People can call in and talk to their favorite celebrity" when making donations, Ziskin said.
Mariah Carey, Beyonce, Mary J. Blige and Rihanna are among a group of singers who will debut their single, "Just Stand Up," which will benefit cancer research.
The aim of the event is to encourage scientists to work together to improve overall cancer care and prognoses, Ziskin said.
"This is what we're asking the whole cancer community to do," she said. "Put aside your competitive issues and come together for the greater good."
ABC is owned by The Walt Disney Co.; NBC is a unit of the General Electric Co.; CBS is owned by CBS Corp.
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