The 74 year old was told she only has three to six months to live after she was diagnosed with terminal brain cancer earlier this year (13).
The Mary Tyler Moore Show star was given a standing ovation during her appearance at the dance show's launch night on Monday (16Sep13) and she is hoping her gutsy decision to take part will inspire other cancer patients.
Harper tells In Touch magazine, "I think the show will play a major part in my recovery... At first I didn't really want to do it. I really love the show, but I was afraid... I prefer to live as though this is all we have, because we could drop dead at any given moment. When life asks you to dance, you just have to dance."
The new season of the hit Tv contest show was launched with a star-studded audience as Jennifer Lopez arrived at the studio with her boyfriend Casper Smart to support best friend Leah Remini, while Ozzy and Sharon Osbourne cheered for their son Jack.