Tony Bennett's Nude Sketch of Lady Gaga for Sale...Wait, What?!

Lady Gaga Ebay Drawing, Tony Bennettebay.com, Kevin Winter/Getty Images

Holy fame monster!

As Vanity Fair subscribers may already know, January cover girl Lady Gaga didn't just get her pose on for famed photographer Annie Leibovitz.

The pop superstar also stripped down to her born-this-way suit for none other than iconic croonerand accomplished artistTony Bennett, whose charcoal sketch of Gaga debuted in the magazine and is now up for auction on eBay, with all proceeds going to charity.

And, trust us, the only thing missing here is the Heart of the Ocean...

MORE: Lady Gaga "Tramps" It Up With Tony Bennett in New Music Video

The original portrait of a nude Lady Gaga stretched out and propped up on her elbows was drawn with Prismacolor Premier Art vine charcoal sticks on Fabriano Artistico heavyweight watercolor paper measuring 18 inches by 24 inches.

Bennett signed the work "Benedetto," as he does with all of his paintings and drawings.

Lady Gaga Ebay Drawing, Tony Bennettebay.com

At press time, the going price was $5,400 with five days and 21 hours left to go. The dough will benefit Gaga's Born This Way Foundation and Bennett's Exploring the Arts, which he founded with wife Susan Benedetto.

And now this whole what-was-Benn! ett-doin g-seeing-Gaga-naked thing makes much more sense, doesn't it? A rumor got out that the octogenarian walked in on his fellow Grammy winner during a recording session for their duet on "The Lady Is a Tramp."

Bennett had actually been invited to Gaga's top-secret photo shoot with Leibovitzwhere obviously nudity was part of the deal.

"Lady Gaga has the mark of true genius in which she makes what is difficult appear effortless," Bennett said of his latest muse. "Fred Astaire, Cary Grant, Ella Fitzgeraldthey all shared that quality and it's what I refer to as the 'It Factor.'"

Funny, we were going to call it the "X Factor" in this case.

GALLERY: Lady Gaga, fully clothed