"I'm really excited to do this," Arquette said. "Part of the opportunity it provides is for people to get a better understanding of who I am and get to know me a little better."
The same goes for activist Chaz Bono.
"I think it's going to be a fun experience that I want to enjoy every moment of," Bono said. "I want to do the best job that I can. And yeah, I think people are going to get to see another side of me. Usually I'm serious, talking about issues. Now I just get to dance. "
U.S. soccer star Hope Solo hopes people will learn more about her sport.
"You know, we're continuing to gain exposure to women's soccer, and whether it's female fans or little kids, now it's becoming male fans and adult fans, and it's one step at a time, but that's our job as professional athletes. It's to grow the sport," she said.
For several cast members, the reason for dancing is charity-driven.
Ricki Lake is donating her paychecks to a nonprofit orphanage and school in Malawi that was opened by her friend.
"She's gone on to open a secondary school, feeding and educating 400 orphans - one woman - and look what one person can do," Lake said.
Chynna Phillips said she's dancing for the homeless kids in Tijuana.
"I'm dancing because there are 40,000 homeless children on the streets of Tijuana and I'm doing every effort that I can to get them off the streets because Tijuana is our backyard," Phillips said.
Nancy Grace said she's happy to give her money to the National Center for Missing & Exploited Children.
"I talk about it every night almost on my HLN show, and now I can put my money where my mouth is," Grace said.
Los Angeles Lakers forward Ron Artest has a very personal reason to dance. It involves his daughter, Diamond.
"When I first had the opportunity to do 'Dancing With The Stars' I wasn't going to do it, then my daughter said 'Dad, you should do it.' She had cancer when she was 4. So I said, 'OK. How about we just dance for cancer?' So all my profits are going to go to the Cancer Research Foundation because of Diamond."
Rounding out the cast are J.R. Martinez of "All My Children," reality TV stars Kristin Cavallari and Rob Kardashian, TV host Carson Kressley and host-model Elisabetta Canalis.