ABC News September 4, 2013

Why Valerie Harper Did 'Dancing With the Stars': 'Don't Die Until You're Dead'

WATCH: Valarie Harper on 'Dancing With the Stars'

"Don't die until you're dead!" exclaimed Valerie Harper, 74, when asked why she decided to do "Dancing With the Stars."

The former "Mary Tyler Moore Show" star, who was diagnosed with terminal cancer earlier in the year, told ABC News today at the "DWTS" cast reveal, "Don't give up on your life. Till God strikes you dead, don't just lay there."

Harper definitely hasn't given up on her life since her grim diagnosis in January. She is now eight months removed from that doctor's visit, when she was told she had three to six months left to live.

Harper added that based on recent scans, the cancer may have retreated for now. She emphasized that it's close to remission, but not quite there.

Read: Valerie Harper, Fighting Cancer, 'Defies the Odds'

So who pushed the "Rhoda" star to accept the invitation to "Dancing With the Stars," which premiers Sept. 16?

"My husband, Tony Cacciotti," she said. "He said, 'You got to do it.' I said, "Never! I'm too heavy, look at these girls, they are in fabulous shape." But he pushed every button he could. He said, 'You do it 'cause you have cancer.'"

Harper said her husband wouldn't let her pass up this opportunity the show had given her to inspire others who have a debilitating disease.

"Just to let people know they can do it too. I was a professional dancer 40 years ago," she said. "I didn't want to go out there and be fat and be inadequate, but I have cancer, so it behooves me to go out there."

Plus, she said the show was actually part of her doctors' orders.

"The doctors want me to exercise!" she said. "I asked, 'What do you think?' They said, 'Fine, if you feel like it and you think you can, go for it.'"

Related: Valerie Harper Diagnosed With Terminal Brain Cancer

Harper, even facing terminal cancer, hasn't lost her famous sense of humor.

"I don't know if I put up the producers' insurance rates sky high by joining," she joked. "[My husband] he's proud, he's proud of me, but he's also saying, 'Get to bed' and 'Eat the right food' and 'Why did you put honey in your tea?'"