Audiences at off-Broadway’s Sleep No More are required to wear Venetian masks throughout the show, and it turned out there was a famous face behind one of those disguises on October 23. Grammy winner Pink was in attendance at the McKittrick Hotel that night, and after the performance the pop star (who's currently filming the sex addiction comedy Thanks for Sharing alongside The Book of Mormon's Josh Gad) took the stage in the Manderlay Bar reception area. Joined by Sleep No More’s resident nightclub performer Stella Sinclair (Karen Marie Richardson), Pink tore into a jazzy rendition of “Summertime” from Porgy and Bess. The singer enjoyed herself so much she took to her Twitter page to declare, "I usually don't like to tell people what to do...but screw it...go see Sleep No More if you're in NYC. It's a once in a lifetime thing." Watch the video below and be sure to head to Sleep No More…you never know what stars might show up!