NEW YORK—What happened to the giant Calvin Klein billboard at Broadway and Lafayette? Was it the “splasher” (the artist who made headlines defacing murals and street art in Brooklyn and Lower Manhattan over the summer) who covered the black-and-white sign in dripping magenta paint? No—it was the New Museum.

At the beginning of the week, paint ran down the center of the sign—prompting a flutter of speculation about who was responsible—and yesterday, more magenta appeared, with a stencil in the middle, in the shape of the New Museum’s illustrious, towering new building designed by Tokyo-based architects Sejima + Nishizawa / SANAA (the outline of which has become ubiquitous around New York as the institution prepares to open the impressive new location on the Bowery and is running an equally splashy publicity campaign). Today, the billboard was entirely covered in drips, with the New Museum stencil highlighted and the museum’s name and December 1 opening date emblazoned on the ad.

ARTINFO caught up with the museum’s director of external affairs, Karen Wong, who admitted the New Museum did the deed—with Calvin Klein’s permission, of course.

“Calvin Klein is one of our inaugural sponsors, and we wanted to do something super crazy,” Wong said. “This is art, it’s fashion, it’s graffiti, and it pays homage to the Bowery in a fun and fresh way.”

But no one we know caught a glimpse of artists actually applying the paint; it just seemed to appear out of nowhere.

“They’ve been doing it in the middle of the night,” Wong said. “We thought we might get a couple of real graffiti artists to come and scale the building at night, with the owner’s permission, but there were too many insurance and liability issues.” Instead, designers created different canvas billboards to install each night, involving a technically complicated process that included superimposing photographs of paint drips. The final billboard will be up through December 3.

The big reveal came just in time for an exclusive “First Look” party tonight, expected to draw high-profile guests including actors Julianne Moore and Maggie Gyllenhaal and hosted by the New Museum and—you guessed it—Calvin Klein.