"He (pro partner Tristan MacManus) says, 'Do you want to get water?' Which is great because I don't drink enough water but (that's) not to do with the cancer ... (it's) not an impediment to dancing and I just try to stay healthy and continue to lose weight so I look halfway decent in the costumes," she said with a laugh.
Harper said of her decision to join the show: "There's a (Lee Ann Womack) country song (with the lyrics) 'when you get the choice you sit it out or dance/ I hope you dance.'"
Other contestants on the new season of "Dancing," which premieres Sept. 16, are Bill Nye, the "Science Guy"; "Pretty Little Liars" actor Brant Daugherty; former NFL wide receiver Keyshawn Johnson; singer-actress Christina Milian; actress Elizabeth Berkley; "High School Musical" actor Corbin Bleu; "Glee" actress Amber Riley; country comic Bill Engvall; and "King of Queens" actress Leah Remini.
The celebrities and their pro partners, minus Remini and dancer Tony Dovolani, all made the trek to New York to promote the show's return.
Although still a ratings winner for ABC in its 16th season, the celebrity dancing contest has seen its overall audience decline and grow older, an issue for networks that get higher commercial ad rates for younger viewers.
"Dancing" will now air once a week on Mondays rather than Mondays and Tuesdays.
"One day a week is fine with me! I need more time to rehearse," said Milian.
"You get all the action in one night. It's all killer, no filler," said her partner, Mark Ballas.
And with younger contestants like Bleu, Daugherty and Riley, the show might skew to a more youthful demo.
There are changes behind the scenes, too. There are new professional dancers, plucked from the show's troupe. Contestants are starting off with a four-hour rehearsal limit per day that will hopefully cut down on injuries and fatigue.
The pros were mixed on whether they liked the time constraint and said it could change as the season goes on and they have to do more than one dance per show.
"Now that we have a restricted time, I feel like we're gonna get more done," said Derek Hough.
"That I don't like," said Karina Smirnoff. "Four hours is tough."
"Every single time that last hour (of rehearsal) ends up coming up with both of us going, 'Oh no. It's not there yet,'" said her partner Bleu.
Smirnoff said she believes as the season progresses, the rehearsals might get longer.
The one thing the audience likely won't see is twerking, a dance that's been in the spotlight thanks to Miley Cyrus' performance at the MTV Video Music Awards.
"I don't think that's relevant to anything that has to do with class," said dancer Val Chmerkovskiy. "I keep it classy. I want my partners to keep it classy. Twerking is not on the menu."