West Hollywood, California - Billie Eilish rang in her next trip around the sun with a few of her celebrity friends at an epic Christmas-themed birthday bash!

What better way to celebrate a 21st birthday than with a customized candy cane cake, music, and a few A-list buddies?

The Sagittarius singer had a very merry birthday as she was honored by her close friends and her boyfriend Jesse Rutherford.

Over the weekend, attendees and Ms. Eilish shared clips on their respective Instagram stories from the clearly legendary party that took place in West Hollywood.

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The Bad Guy artist and her boo sported matching Mr. and Mrs. Claus outfits, with the birthday girl wearing a tight red strapless dress with faux fur stitched to the top and the bottom.

She completed her b-day look with long red gloves, a black belt, and a matching cloak.

BFFs Kendall Jenner and Hailey Bieber were among those in attendance, and the two dropped a few snaps of their naughty behavior during the party.

The Kardashians star posted pics of their black-and-white photo booth snaps on her IG story, and the two pals had their tongues out and middle fingers blazing.

Per Page Six, Justin Bieber, Lil Nas X, Olivia Rodrigo, Avril Lavigne, and Dove Cameron were also at the festive gathering.

We wonder what celebs ended up on the naughty list after this epic shindig!