LOS ANGELES -- More A-listers have signed on to support the third Stand Up to Cancer telethon.

Organizers say Tom Hanks, Halle Berry, Justin Timberlake, Sofia Vergara, and Olympic gold medalists Gabrielle Douglas and Missy Franklin will participate in the hourlong TV special. It is set to air today on ABC, CBS, NBC, Fox and more than a dozen cable channels.

The slate of stars also includes Eric Stonestreet, Ray Romano, Felicity Huffman, Rocco DiSpirito and Maura Tierney. They'll join previously announced participants such as Julia Roberts, Matt Damon, Michael Douglas, Jessica Biel, Samuel L. Jackson, Jeremy Renner, Seth Rogen, Emma Stone and Gwyneth Paltrow.

Paltrow also is an executive producer of the fundraiser that will be carried commercial-free from 7 to 8 p.m. from the Shrine Auditorium in Los Angeles.

Taylor Swift, Tim McGraw, Coldplay and Alicia Keys are set to perform during the special, and patients participating in Stand Up to Cancer trials will share their experiences.

Stand Up to Cancer has raised more than $180 million for cancer research and awareness since the telethon was established in 2008. The organization said it has awarded grants to seven multidisciplinary research "Dream Teams" and to scientists seeking innovative approaches to end cancer's role as the world's leading cause of death.

The telethon has a celebrity phone bank that allows donors who call in to talk with the stars.

The cable channels carrying the telethon are BIO, Encore, HBO, Showtime, HBO Latino, ION Television, LMN, Logo, MLB Network, mun2, Palladia, Starz, TBS, Smithsonian and VH1.

Stand Up to Cancer was co-founded by "Spider-Man" movie producer Laura Ziskin, who produced its first two telethons in 2008 and 2010. Ziskin lost her seven-year fight against breast cancer last year.