"Stand Up to Cancer" announced Thursday appearances by other actors, athletes and musicians who have faced the disease, including Maura Tierney, Christina Applegate and Kareem Abdul-Jabbar.
Elizabeth Edwards, who kicked off the first "Stand Up to Cancer" telethon in 2008 with Armstrong, is taking part again.
One of the night's musical performances will be led by Stevie Wonder and include Natasha Bedingfield, Queen Latifah, Martina McBride, Aaron Neville and Dave Stewart.
"Stand Up to Cancer" will air commercial-free Sept. 10 (8 p.m.-9 p.m. EDT) on the four major broadcast networks, ABC, CBS, Fox and NBC, as well as on a number of cable channels. News anchors Katie Couric, Diane Sawyer and Brian Williams are the hosts.
Others set to appear include Reese Witherspoon, Mandy Moore, Apolo Anton Ohno and Jim Parsons.
Film and TV producer Laura Ziskin (the "Spider-Man" franchise), a cancer survivor who produced the first telecast, has taken on the job again.
"On Sept. 10, we'll send a resounding message: We can cure cancer. It's going to take guts, brains and the ongoing support of the public, but we can do this," Ziskin said.
The 2008 event helped deliver more than $100 million for research.
The American Association for Cancer Research, the scientific partner of Stand Up to Cancer, administers grants and provides scientific oversight in partnership with a Stand Up to Cancer advisory committee.
Stand Up to Cancer is a program of the Entertainment Industry Foundation, a nonprofit TV and film industry group that supports programs addressing health, education and social issues.
Telethon viewers will be asked to make donations by phone or on the Stand Up to Cancer website. All public donations go to cancer research, the group said.
Besides the broadcast networks, Bio, Discovery Health, E!, G4, HBO, HBO Latino, MLB Network, mun2, Showtime, Smithsonian Channel, The Style Network, TV One and VH1 also will simulcast the event.