ET's CHERYL WOODCOCK is exclusively backstage with "Dancing with the Stars"' LOUIS VAN AMSTEL as the dancer/choreographer rehearses the "DWTS" professional dancers for the opening number of the Race to Erase MS.

This is the 15th year for the charitable gala, organized by NANCY DAVIS, which this year celebrates the theme: "We Heart to Erase MS."

"Our show opens with the 'Dancing with the Stars' cast doing the most amazing dance which they are preparing tonight," Nancy, whose family watches the hit ABC show, tells Cheryl. "That will lead into an amazing TOMMY HILFIGER fashion show that many celebrities are modeling in and a fabulous auction. It is going to be so much fun and it is all about raising money to find a cure for Multiple Sclerosis."

The Race to Erase MS is very personal for Nancy Davis. She explains, "Sometimes in your life things happen to you and they are so devastating you think, 'Why me?' But, out of everything bad comes something good. Later on you wake up and realize, 'Maybe I got this disease for a reason.' It gave me the ability to do something. I was at a very low point in my life and I didn't understand what that was going to mean for my life. I was a young mom with three kids and was told I was never going to walk again. It was very upsetting and devastating. I was lucky I didn't listen to the first doctor."

When Nancy started her work on behalf of MS, there were no drugs on the market. Today, there are six, with a seventh to be introduced shortly.

On hand for the rehearsals were CHERYL BURKE, DEREK HOUGH, KYM JOHNSON, ANNA TREBUNSKAYA, EDYTA SLIWINSKA, KARINA SMIRNOFF, JONATHAN ROBERTS, TONY DOVOLANI and MARK BALLAS.

The 15th Annual Race to Erase MS, with a musical performance by FRANKIE VALLI AND THE FOUR SEASONS, takes place on Friday, May 2 at the Hyatt Century Plaza Hotel. For more information, go to www.erasems.org.