A retrospective of the work of Pop artist Roy Lichtenstein, whose “Sleeping Girl” set an auction record of $45 million last week, will open May 22 at the Art Institute of Chicago. Proving the artist's current popularity, on onslaught of interest from museum members who signed up to attend preview days has delayed the general public's viewing of the exhibit.

More than 3,000 members have registered for preview events, forcing the the museum to add more members-only viewing opportunities and preview days. Some of those events are lectures, accommodating up to 1,000 people, and have already filled up.

This exhibit is considered one of the largest groupings of Lichtenstein’s work, featuring more than 160 drawings, paintings and sculptures.

The retrospective will open to the general public on May 22, when the museum reopens after shutting down for three days due to the NATO summit taking place in Chicago, and will remain on display until Sept. 3.