For many of the famous faces in attendance, the connection to the battle against cancer hits close to home.
"I lost my dad when he was 49 to cancer, and I think it would be amazing to think that he could have lived a full life," said "Modern Family" actor Ty Burrell.
And for those entertainers, the desire to turn their losses into something positive is what inspired their actions.
"I lost my mother to ovarian cancer when she was 64 years old, and that loss was so terrible and so devastating to watch, that's when I became an advocate to help raise funding to help scientists to do their research," said film executive Sherry Lansing.
Others were simply thrilled to be part of the event.
"This has done such an incredible job for raising money for research and this is what it's all about, people coming together to help find a cure," said Olympic swimmer Missy Franklin.
But the true stars are the cancer patients. The show featured personal stories of people like Hillary Kind, a Michigan resident who has terminal melanoma.
"I want people to know about skin cancer, learn what it is and not just think that it's just a stupid cancer you can get shaved off in two seconds, because it's not," she said.
"Stand Up to Cancer" has raised $180 million over the past four years. But some say the ultimate goal is about something else.
"The goal that is set forever is that cancer be no more," said Lansing. "We want to be out of business -- that's the goal that we want."
Taylor Swift debuted a special song for a young cancer victim on the telethon.
"Ronan" is dedicated to a 3-year-old boy who died in 2011 of neuroblastoma. Swift wrote the song after she read a blog by the child's mother, Maya Thompson, who is credited as a co-writer.
According to a source familiar with the show, the song has never been performed in public. After the telethon, it will be available on iTunes with proceeds going to cancer-related charities.
"Stand Up to Cancer" aired at 8 p.m. on all the major networks, including ABC7.
In addition to Swift, other musical guests included Coldplay, Alicia Keys and Tim McGraw. Other celebrities taking part include Tom Hanks, Julia Roberts, Gwyneth Paltrow, Justin Timberlake, Samuel L. Jackson, Emma Stone and more.
Paltrow served as an executive producer for the telethon.
If you missed the telethon, you can still donate. Phone operators are working through the weekend. The number to call is (888) 90-STAND.
The Associated Press contributed to this report.