After Monday night’s glitzy Met Gala, celebs fanned out to hit over-the-top after-parties — but even some A-list stars had trouble getting in!

A source tells us that “Unholy” singer Sam Smith — who uses they/them pronouns — was turned away from a Macallan bash at the Mark Hotel.

We’re told the highly recognizable crooner was rebuffed — and told, “You’re not on the list, you can’t come in” — despite their hit-making status, plus the fact they were staying at the luxe hotel.

“They gave them a flat out ‘no.’ They tried three times,” said our spy.

We hear that Smith — who earlier attended the Met Gala with designer beau Christian Cowan — did not throw a diva fit.

“They walked out surprised,” says our source, “But Sam was totally cool and polite.”

Smith shouldn’t feel too bad. Last year, Page Six exclusively reported that Kylie Jenner was turned away from Richie Akiva, Doja Cat and Diddy’s party at the Box because it was at capacity.

In 2016, Page Six also exclusively reported that Tesla mogul Elon Musk was left standing in the rain after being denied from a party at the Top of the Standard.

“Everyone was shouting and trying to help, saying, ‘He’s Elon Musk!’ And they were just like, ‘We don’t care, he’s not on the list,’” said a spy at the time.

Either way, the rejection didn’t put a damper on Smith’s night: The singer was spotted at Dua Lipa’s bash at Rob Toma’s Hearsay in the Meatpacking District, as well as at a number of other Met Gala celebrations.

A source tells us, Smith and Cowan “kept the dance floor smoking hot.”

Also spotted were billionaire Jeff Bezos and his fiancée Lauren Sanchez, and a spy said the couple had no less than seven bodyguards with them!

“SNL” star Kenan Thompson, who separated from his wife Christina Evangeline in April 2022, was seen wearing sunglasses on the dance floor and hanging out with three women, says a witness.

Meanwhile, exes Kendall Jenner and Bad Bunny were spotted looking cozy at the Après Met 2 Met Gala hosted by Emily Ratajkowski.

Speaking of exes — on/off couple Cardi B and Offset, who had a public split in December, were seen together at Richie Akiva and Ray Ban’s party at Casa Cirpiani.

“They came in super late and were holding hands and by each other’s sides the whole time,” says our spy. “They seemed like they were a couple.”

Their reps did not respond to a request for comment, and Cardi also hosted a bash at Silencio.

“Elvis” director Baz Luhrmann was spotted dancing at the same bash — with Lizzo and Sza — and the fete went till 5a.m. We hear that Usher, Lil Nas X and Alton Mason started a dance circle with the crowd cheering them on, and that Sam Smith was also at the party.

Over at the Standard — where Smith was again briefly spotted — FKA Twigs hosted a party that brought out guests like Camila Cabello, Prabal Gurung, Lourdes Leon, LaQuan Smith and Tessa Thompson.