Watch the exact moment Billie Eilish came up with 'Barbie' song 'What Was I Made For?'

Billie Eilish and Finneas' existential Barbie soundtrack song, "What Was I Made For?" is so polished and popular that it's difficult to imagine the two of them struggling to come up with it.

But as Eilish explains to Jimmy Kimmel in the clip above, they spent a good six hours flailing before everything finally clicked. The duo spent the past year filming all their recording sessions, and they showed the exact moment where Eilish suddenly comes up with the "What was I made for?" hook at the heart of the song.

"We finished it with 'What was I made for?' and that full sentence was like oh, OK, we're doing this," Eilish grins.