Lady Gaga nude sketch by Tony Bennett to be auctioned for charity

(CBS) A nude sketch of Lady Gaga drawn by Tony Bennett will be sold at auction, with the proceeds going to charity.

Drawn in charcoal on paper, the portrait was made while the singer posed for Bennett and photographer Annie Leibovitz for the January issue of Vanity Fair magazine. It's signed under his given name, "Benedetto," which he uses for his original artwork.

Pictures: Lady Gaga
Pictures: Tony Bennett

It will be sold via eBay.com/celebrity, which allows stars to auction off items for charitable causes. Bidding begins Monday and ends Dec. 19.

Other items in the sale include accessories Lady Gaga wore for the Vanity Fair photo shoot - Mercura sunglasses, House of Lavande earrings, an Alexis Bittar ring and a pair of Brian Atwood shoes - and a poster of the magazine's January cover signed by the singer. There's also a print of the cover's photograph signed by Leibovitz and a limited-edition print of Bennett's watercolor "Gondola, Venice."

All proceeds from the auction will benefit Exploring the Arts, a nonprofit founded by Bennett and his wife to strengthen the role of the arts in public high school education, and the Born This Way Foundation, an organization founded by Lady Gaga that focuses on youth empowerment.

This isn't Bennett and Gaga's first collaboration - they also recorded a rendition of "The Lady is a Tramp" for Bennett's album "Duets II."