*Will Smith and Denzel Washington have been added to the lineup of the telethon “Stand Up to Cancer,” airing Sept. 10 at 8 p.m. across multiple networks.

George Clooney, Gwyneth Paltrow and Renee Zellweger will also appear on the fundraiser, which will be preceded by an online pre-show hosted by Cat Deeley of Fox’s “So You Think You Can Dance.”

Other additions to the lineup include: Elizabeth Banks, Kathy Bates, Emily Deschanel, Bill Hader, Dorothy Hamill, Anne Heche, Cheryl Hines, Rob Lowe, Marlee Matlin and Olivia Munn.

Musical guests include Billie Joe Armstrong of Green Day, Neil Diamond, The Edge, Herbie Hancock, Kris Kristofferson, Lady Antebellum and Leona Lewis.

Stand Up to Cancer will be simulcast commercial-free on ABC, CBS, FOX, NBC, Bio, Current TV, Discovery Health, E!, G4, HBO, HBO Latino, MLB Network, mun2, Showtime, Smithsonian Channel, The Style Network, TV One and VH1. Network news anchors Katie Couric, Diane Sawyer and Brian Williams will host the event.

The broadcast will air in 195 countries, as well as on the Armed Forces Network.

SU2C co-founder Laura Ziskin, the broadcast’s executive producer and a cancer survivor herself, urged viewers in a statement “to see your favorite stars, who’llask, ‘Will you stand up with us?’Person by person, saying ‘yes’ moves us toward a goalcompletely within our grasp: a world without cancer.A donation of any size brings scientists one step closer to a cure.”

The Deeley-hosted pre-show will kick off the evening as the celebrity phone bank opens a half-hour before airtime.

Also online, and following the show: a 30-minute jam session featuring musical guests Fitz and the Tantrums, Orianthi, Natasha Bedingfield and Heart.