With her brother Finneas at the piano, Eilish was seated on the steps of a beautiful theater and gave a smoldering performance of the song from the upcoming James Bond film.
Read MoreBefore their performance, the brother-sister musical powerhouse chatted with Jimmy Fallon about the “crazy, surreal” experience of how they got the opportunity to write the next 007 theme song.
“I don’t know when it was real,” Eilish said. “But I do know, for many years, we’ve wanted to write a Bond song, not even [that] we thought we could. It was more like a fantasy, like a complete fantasy, like, ‘How cool would it be to do this?'”
When it came to writing the song, Eilish explained that “We kind of started with making a melody that we knew was really solid before we tried any lyrics out. But we did definitely, before we had written anything, go… we knew how important it was to have the title of the movie in the song and have the song be called that because it wouldn’t have been satisfying otherwise.”