The Museum of Modern Art is closing its Marcel Duchamp retrospective on Sunday, August 23, and the entire final day belongs to members. MoMA calls it Last Look: Marcel Duchamp, and according to the membership emails the museum sent out, it runs from 9:30 a.m. to 5:30 p.m. at MoMA’s building at 11 West 53 Street in Manhattan.

Here’s the catch, and it’s the whole point: the last day of every major exhibition at MoMA is reserved just for members. If you were planning to walk in off the street on August 23 to catch Duchamp before it’s gone, you can’t. You need a membership to get in that day.

The show itself is a big one. It traces nearly seven decades of Marcel Duchamp’s practice and features more than 300 artworks, according to MoMA. Even if you’ve already seen it, the museum says the exhibition “always contains more to be revealed.”