Billie Eilish Performs "Copycat" at the Mahogany Session in 2017
Sometimes all Billie Eilish needs is her brother Finneas O'Connell on the guitar and backup vocals for a compelling performance. That's what's happening here in this stripped-down rendition of "Copycat," a song that showcases the gorgeous range of her voice. That said, her hoop earrings and black-spiked choker look fantastic.