Whitney DuncanWhitney Duncan continues her charitable ways this holiday season. The singer is offering the dress off her back! But not just any dress -- the stunning purple number she wore to this year's CMA Awards.

The authentic Italian Versace gown has a halter neckline and empire waist. Bidding on it has begun at eBay and continues until Saturday ( Dec. 19).

Proceeds from the auction will support Country Cares for St. Jude. "I really admire the hope that St. Jude offers families who are going through such a difficult season in their lives," says Whitney. "Just because you're not in the same battle doesn't mean you can't help fight the disease with them in any way you can – every little bit counts."

Whitney and her purple Versace made the Tennessean's CMA Best Dressed list, joined by Carrie Underwood, Taylor Swift and Faith Hill.