Inside Billie Eilish’s 21st birthday party: See her holiday-inspired, PDA-packed bash By . Caroline Blair. Published Dec. 19, 2022, 3:35 p.m. ET. A very merry 21st birthday!

A very classic 21st birthday party romp: casino night. Find a joint in your area (or plan a Vegas trip if you’re going all out), squeeze into an aughts-era bandage dress, and try your gambling luck.