Enjoy every minute. Time to go back to the ballroom. The new season of "dancing with the stars" remepremiers tonight. Melissa rycroft behind the scenes with the final rehearsals. Should we say former... See More
Enjoy every minute. Time to go back to the ballroom. The new season of "dancing with the stars" remepremiers tonight. Melissa rycroft behind the scenes with the final rehearsals. Should we say former champion? I love that. Been there, done that. Happy to be on this side of things now. I definitely know firsthand how tough the rehearsals can be on your body and your nerves. This year's group of competitors are feeling the heat, too, with the added pressure that your first dance could be your last. They're ready. But, nervous? Yes. Reporter: Yeah in. Definitely. Reporter: We're no the ballroom. What are you thinking? It was a lot mf nerves than i thaulgt it would be. You look terrified. Fair tied? Yeah. Reporter: It's just a dance floor. Millions of people. A dance show that this season has restricted the couples' initial reversals to just four hours each day. Peta is intimidated when she wants to be. She seems sweet and unassuming. I have this look. Reporter: Can I see it? And what is your reaction? I start sweating. Reporter: Tonight, they'll cha-cha, fox trot, and contemporary dance. What are you finding most difficult in rehearsal that you didn't expeekt? It's not that she's difficult. She's the easiest person to get along with. We laugh and have fun. She's just -- she's tough. She cracks the whip. Reporter: How are you feeling? Good. Reporter: Really? I am. I have a sprained knee. I wouldn't be doing this if it was endangering me in any way. I thing it was a great opportunity to get out there and say, you know, I have cancer. Keep living your life. Keep moving. You can win. You can extend the time at least. One thing I want to accomplish is mainly to put it out there in all seriousness, when you get diagnosed with m.S. That your life doesn't stop. You're still for the most part able to do what everyone else can. Is. Reporter: What do you hope to accomplish? I want young girls that look like me to get out there and move. Reporter: You're a new mom. How hold is he? He's 1. Reporter: Do you see anybody here at competition? I don't see anybody who is not competition. I see every one of them if i understand the term, a threat. Reporter: Potential threats include jersey shore's snooki, football's keyshawn johnson and actress singer song write r krit tina millian. Now, it's leah remini's turn with tony. Reporter: I'm your baby. Until now. Previous partner she's talking about. Why don't you dance with her. Screw this. Screw the interview. Why didn't you help me out with that one? Reporter: I wasn't expecting you to walk right into it. I had so much fun getting to meet the new cast. I think they'll be phenomenal. Little known fact, karina smirnoff starts every show eating dark clock lat. We surprised her. She instagramed a fun thank you. Maybe tony can take some notes. Melissa, thank you. Great to see you. Can't wait for tonight. It all begins tonight. And linda ronstadt when we
This transcript has been automatically generated and may not be 100% accurate.