The cast and crew spent two days shooting at the McKittrick Hotel, a five-story commercial space located at 530 West 27th Street, which has been transformed to house the Macbeth-inspired Sleep No More. Actors from Sleep No More were also involved in the shoot. Andy Wolk directed the episode written by Dan Steele.

Here's how the CW describes the upcoming episode: "Several of our favorite Upper East Siders attend a performance of Punchdrunk's provocative theater experience, Sleep No More, which translates to masks, anonymity and some surprising romantic twists by the end of the evening. Meanwhile, Diana (guest star Elizabeth Hurley) sets her sights on Serena in her quest to ruin Gossip Girl. Dan is out on his book tour, but things aren't exactly as they appear to his friends and family."

"Gossip Girl" airs Monday nights at 8 PM ET. Check local listings.

For more information on Sleep No More, visit sleepnomorenyc.com.

To watch the "Gossip Girl" preview, look below: