First Fashion Fan Michelle Obama joined a who’s who of top designers Monday morning to cut the ribbon at the Metropolitan Museum’s new Anna Wintour Costume Center.

Calvin Klein, Michael Kors, Donatella Versace, Carolina Herrera, Tory Burch, Marc Jacobs, Victoria Beckham, Donna Karan, Ralph Lauren, and Mary Kate and Ashley Olsen were among the fashion luminaries at the $40 million center, named for the famed Vogue editrix.

“It was lovely, it was remarkable actually,” cooed Grace Coddington, Vogue’s creative director, after leaving the event, which shut down Fifth Avenue in front of the museum.

Wintour — the inspiration for the novel and film “The Devil Wears Prada” — raised more than $500,000 for the president’s 2012 re-election, putting her among the top tier of his supporters.

Wintour was also instrumental in promoting “Runway to Win,” in which she enlisted top designers like Jacobs and Alexandra Wang to make swag to raise funds for the campaign.

Michelle Obama was later expected at a pair of Democratic fundraisers in the city.

A new exhibit at the center will open to the public Thursday featuring the work of Charles James, known as America’s first and really only couturier until his death in 1978.

His clients from the 1930s to the 1950s included Gypsy Rose Lee, Marlene Dietrich and Mrs. William Randolph Hearst Jr. His clothes — revolutionary in their time — had a huge influence on modern fashion.

Christian Dior called him “the greatest talent of my generation.”

The show, “Charles James: Beyond Fashion,” emphasizes technology. In a large ground-floor gallery, animated videos illustrate how each gown was constructed, from the original piece of fabric to the intricate completed garment.