Inside Kaia Gerber's 21st Birthday Party -- and Why Boyfriend Austin Butler Was Not There

Kaia Gerber
Jake Cloobeck

Kaia Gerber kicked off September with a special occasion: her 21st birthday!

Fashion month may have only just begun, but Kaia Gerber kicked it off in style. Cindy Crawford's daughter celebrated her 21st birthday on Saturday with a star-studded gathering at Los Angeles nightclub, Offsunset, a source confirmed to ET. 

"Billie Eilish, Finneas O’Connell, Camila Morrone, Evan Ross, Paris Jackson, Roddy Ricch and Madison Beer were all in attendance," the source said, "and Kaytranada did a surprise performance with Roddy Ricch for Kaia."

According to the source, the birthday girl "had a bast" during her special night, including singing and dancing to Cyndi Lauper's "Girls Just Want to Have Fun" with Ross. "Kaia put on a crystal tiara towards the end of the night," the source shared, "and danced with Billie and Camila."

Speaking of Morrone, who recently split from boyfriend Leonardo DiCaprio, the actress was spotted "dancing, smiling and partying," the source described. 

Jake Cloobeck
Jake Cloobeck
Jake Cloobeck

One famous face who was missing from the celebrity soirée? Austin Butler. According to the source, Gerber's boyfriend was supposed to attend, but the Elvis star couldn't make it at the last minute. 

"Kaia didn’t seem bothered by it at all," the source noted, "and was having an amazing time."

Of course, Gerber's famous mama took to social media with birthday wishes for her only daughter. "@kaiagerber, how are you 21 already?! I am so proud of the woman you have become and how you are in the world. Your curiosity, kindness and sense of adventure continue to inspire me," Crawford wrote on Instagram. "I’m so happy to be on this life journey with you! Continue to thrive this year and always — with so much love ❤️ Mom."

As for the birthday gal, Gerber commemorated the occasion with a snap of herself asleep in bed. The fitting caption? "21."

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