The 'Mary the Night' singer recently posed nude so the 85-year-old crooner could draw pictures of her after they recorded a song for his 'Duets II' album, with the session captured by celebrity photographer Annie Leibovitz, and the drawing will now go be sold via internet auction site eBay.
Other items to go under the hammer include the accessories Gaga wore for Annie's photos – which appear in the current issue of Vanity Fair - including Mercura sunglasses, House of Lavande earrings, an Alexis Bittar ring and a pair of Brian Atwood shoes.
An original print of the Vanity Fair cover image of Gaga autographed by the photographer and a poster of the cover signed by the singer will also be sold to raise money for Exploring the Arts and the Born This Way Foundation.
Speaking previously about posing naked for Tony, Gaga, 25, said: "I walked in and said, 'Well Tony here we are,' and I dropped my robe and I got into position. I felt shy and thought, 'It's Tony Bennett, why am I naked?'
"Oh Tony he's so handsome. I feel terrible whenever his wife is around because he is so charming and such a gentleman."