Billie Eilish sings Oscar-nominated 'Barbie' song

Billie Eilish (Getty Images)

Billie Eilish and brother Finneas O'Connell performed a moving rendition of their Oscar-nominated song from Greta Gerwig's "Barbie."

Finneas sat at the piano while Billie stood at the microphone to sing "What Was I Made For?" at the Dolby Theatre in Los Angeles, Calif., for the 96th annual Academy Awards.