Actress Tilda Swinton is making an unannounced performance of her 1995 piece "The Maybe" right now at the Musuem of Modern Art in Manhattan. She'll do it on random days over the next month, and even the museum staff won't know she's coming til the night before.

"She's there today. She'll be there the whole day. All that's in the box is cushions and a water jug," a MoMA source told Gothamist.

Swinton, 52, first did the performance piece at London's Serptentine Gallery in collaboration with British sculptor Cornelia Parker and actress Joanna Scanlan in 1995; she slept in the glass box for a week. In 1996 she repeated the performance in Rome at the Museo Barracco.

MoMA said the whole point is that there isn't a schedule, a press release, or artist statement. "Those who find it chance upon it for themselves, live and in real—shared—time: now we see it, now we don't," is all they would say.

Swinton won Best Supporting Actress at the Academy Awards in 2007 for Michael Clayton. More recently, she played a social worker in Wes Anderson's Moonrise Kingdom. This week, she made a speech at the opening of the David Bowie exhibit at the Victoria & Albert Museum in London—she plays his wife in his new music video for "The Stars (Are Out Tonight)", presumably quashing the internet theory that Bowie and Swinton are actually the same person.

Go see her for yourself at MoMA at 53rd Street and 6th Avenue until 5:30 p.m today.

RELATED: 25 Actors Who Are Crazy in Real Life 

RELATED: The 100 Best Movies of the Complex Decade 

[via Gothamist]