Metropolitan Museum of Art executives are set to hold an emergency meeting Sunday over their decision  to honor notorious “antisemite” John Galliano at their Met Gala nest year, just as City Council Speaker Julie Menin slammed the institution for making a “serious mistake,” The Post has learned.

Museum executives scheduled an impromptu session after growing fallout over their plans to host the “John Galliano: Horizons” exhibit at their Met Gala 2027 fundraiser in May, an insider confirmed to The Post.

Galliano was convicted of a hate crime in 2011 for drunkenly berating patrons at a Paris bar with antisemitic insults, and proclaiming “I love Hitler” in a disturbing incident that got him booted from his cushy gig at Dior.

Menin, in a scathing letter, demanded the Met reconsider planning the annual fundraiser’s theme around the disgraced designer — telling organizer Anna Wintour that Galliano does not meet the standards of the prestigious museum.

“In a time of rampant anti-Semitism in our city, I believe honoring John Galliano is a serious mistake. I urge the Met to reconsider this decision as choosing to bestow the highest honor the museum has to someone who has a history of anti-Semitic and anti-Asian slurs only serves to fan the flames of hate and sends the message of a normalization of this type of conduct,” Menin, who is Jewish, told The Post Saturday.

“I am also deeply troubled by reports that there is a more recent 2019 incident that was never investigated. As the daughter of a Holocaust survivor and the first Jewish speaker of the New York City Council, I strongly urge the Met to reconsider honoring Galliano.”

The letter marks the first time the Menin has spoken out about the controversial exhibit, which will be on view at the Met for nine months next year.

Antisemitism activists also slammed the Met for hosting the “hateful” designer.

“Anna Wintour must be awfully comfortable embracing a Nazi-loving antisemite to put the prestige of the Met behind his rehabilitation,” Brooke Goldstein, founder of End Jew Hatred, an organization that combats antisemitism, told The Post.

“The Met took the risk because they thought they could get away with it, I don’t think they would book a figure who was convicted of other forms of discrimination; it’s in vogue to overlook antisemitism in this industry,” Eitan Guttenmacher, executive director of Havura, a Jewish artists group, added.

The nod to Galliano will kick off with the annual Met Gala, which typically is hosted on the first Monday in May — which lands on May 3 next year, Holocaust and Heroism Remembrance Day.

The one-time Christian Dior creative director would be the third living person to ever receive the solo retrospective, following Yves Saint Laurent in 1983 and Rei Kawakubo in 2017.

Menin is one of the biggest voices to publicly blast the announcement, joining leaders from art and Jewish institutions who raised concerns earlier this month.

Her demands were addressed to Wintour, as well as Max Hollein and Andrew Bolton, the respective CEO and Wendy Yu Curator in Charge of The Costume Institute at the Met.

The Met did not respond to The Post’s request for comment.

Hollein, In a statement to the New York Times, said: “The Met has no tolerance for antisemitism, racism or prejudice of any kind. We are in close consultation with Jewish leaders and other stakeholders, and we take the concerns we’ve heard very seriously.”

Wintour, the Met trustee and Vogue’s global editorial director, reportedly met with New York City’s “influential rabbis and Jewish leaders” on Galliano’s honor, who ultimately gave her their blessing and said he deserves a second chance.

The museum promised the exhibit would “directly address the rupture caused by his antisemitic, racist, and anti-Asian conduct” in 2010 and 2011.

Galliano later apologized, claiming that he didn’t recall the incidents and had suffered from alcoholism and drug addiction.

He took a hiatus from the fashion world and sought rehab before returning in 2014 for a role as Maison Margiela’s creative designer.

Galliano was accused of carrying out another antisemitic rant in 2019 against fashion publicist Lauren London, who told The Times he repeatedly screamed “Merry Christmas” at her while she spoke to her daughter over the phone in Hebrew.

A spokesperson for Galliano denied the 2019 allegations to The Times.