Inside Rihanna’s star-studded Met Gala afterparty

Rihanna rolled up to her own Met Gala afterparty after 2 a.m. Tuesday at NYC club Up & Down, having changed from her “papal chic” outfit to “pajamas.”

The “Umbrella” singer had changed out of her showstopping ensemble from the Metropolitan Museum benefit into “a silver two-piece pajama-looking pantsuit,” a spy said, with “gray glasses and cross chains.”

But that didn’t mean RiRi’s bash was a sleepy kind of affair.

At the party was a starry crowd, including Bella and Gigi Hadid, Hailey Baldwin with singer Shawn Mendes, Kendall Jenner, Diddy, Pharrell Williams, Ansel Elgort, Mary J. Blige, artist Maurizio Cattelan, and designers Alexander Wang, Olivier Rousteing and Riccardo Tisci.

Sources told Page Six that Donald Glover performed as his alter ego, rapper Childish Gambino.

Will Smith and Jada Pinkett Smith’s son, Jaden Smith, also was a surprise performer and he “passed the mic to Diddy’s son Christian ‘King’ Combs, while Janelle Monáe and Trevor Noah had a dance-off.”

Meanwhile, rapper 2 Chainz “was snuggled up with” Kesha Ward, whom he’d proposed to (again) on the Met Gala red carpet earlier in the night, while Idris Elba hung out with his fiancée, Sabrina Dhowre.

Newlyweds Emily Ratajkowski and Sebastian Bear-McClard partied ’til 4 a.m., when Rihanna headed with her nightlife impresario pal Richie Akiva and friends to his other spot, 1Oak, to continue celebrating.

Karlie Kloss showed up with long-term boyfriend Josh Kushner, while Tisci hung out with Vogue UK editor Edward Enninful and supermodel and actress Amber Valletta.