“'Bellyache' is totally fictional. I like writing about things that aren't real. The song is about not trusting anyone and then putting trust in yourself and realizing that you don't know what you are doing, either. Or realizing that things you do with a group of people that you think are cool in the moment are ultimately all on you.”

American singer-songwriter

Billie Eilish Pirate Baird O'Connell is an American singer-songwriter known for her distinctive sound and vocal style. She has become a prominent figure in contemporary pop culture. Her music is noted for layered vocals and harmony lines, techniques that build on double tracking. Those choices give her recordings a close, restrained quality that has helped define her public image and her work.