Guests at a fund-raiser for New York State Sen. Brad Hoylman got some unexpected entertainment Monday night when a “zaftig, middle-aged woman playing a piano in the nude” appeared in a window across the street from the power event.

The fund-raiser was going on at the Chelsea home of Christie’s New York e-commerce whiz John Auerbach when the improper pianist suddenly put on a show across the way. (We can’t be sure what tune she played.)

Unwitting audience members marveling at the view included Jonathan Adler and Simon Doonan, Joseph Altuzarra and Seth Weissman, and Hoylman’s husband, David Sigal.

Co-hosts included producer Jordan Roth and Richie Jackson.