Billie Eilish dropped her debut album on Friday and it looks set to be a smash. Like all viral stars worth a million views or more, Eilish appeared on Ellen on Monday. Her time on the show consisted of a performance of "When The Party's Over" plus an interview in which she was pranked, April Fool's-style, by a fake Justin Bieber. Check out her performance above and the interview segments below. Eilish's FADER cover story is here.