Meryl Streep, Forest Whitaker, cancer survivor Lance Armstrong and other celebrities will take part in a three-network telethon to support cancer research, it was announced Tuesday.

The hour-long "Stand Up To Cancer" will air live and commercial-free on ABC, CBS and NBC on Sept. 5 and feature musical performances and appeals from actors, athletes and journalists.

Charlize Theron, Hilary Swank, America Ferrera, Danica Patrick, Salma Hayek, Kirsten Dunst, Josh Brolin, Scarlett Johansson, Jennifer Aniston, Masi Oka and news anchors Charles Gibson, Brian Williams and Katie Couric will be among those taking part.

Former Sen. John Edwards' wife, Elizabeth, and Robin Roberts of ABC's "Good Morning America" also are set to appear. Both women have battled breast cancer.

During the telethon, viewers will be invited to make donations by calling the celebrity-staffed phone bank or by texting.

Musicians and other participants are to be announced, according to a "Stand Up To Cancer" release.

Such network cooperation is rare but not unprecedented. In 2005, the six biggest broadcasters, along with cable channels, carried a Hurricane Katrina benefit program. In 2001, ABC, CBS, NBC and Fox aired a telethon for victims of the Sept. 11 terrorist attacks.

Fox was invited to participate in the cancer telethon but declined.

In a statement Tuesday, Fox called the telethon worthy but said it was focusing on "the global outreach of `Idol Gives Back,'" its charity effort tied to its hit singing contest "American Idol."

Fox will promote the telethon with public service announcements during the broadcast and during some baseball playoff games, the network said.

The telethon is part of a broader initiative aimed at raising money to quicken the pace of research leading to development of new treatments.

The effort is to be administered by the American Association for Cancer Research under the direction of a committee led by Phillip A. Sharp of the David H. Koch Institute for Integrative Cancer Research at MIT.

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(This version CORRECTS that Robin Roberts is on ABC's `Good Morning America' not NBC's `Today.')

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