Inside Billie Eilish's Star-Studded Christmas-Themed 21st Birthday Party

Billie Eilish celebrated her 21st birthday over the weekend with a star-studded Christmas-themed birthday bash. Lil Nas X, Noah Cyrus, Dove Cameron, Kendall Jenner, Hailey Bieber, Justin Bieber, Eric André, Avril Lavigne, Eiza González, Hailee Steinfeld, Skylar Astin and Billie’s boyfriend, Jesse Rutherford, were all in attendance.