Billie Eilish Wrote the Final English Lyric of New Rosalia Collab With Her Entire Family

"So my mom, my dad, Finneas, me, Finneas' girlfriend Claudia, we all came down to the studio, and we listened, and me and Finneas were like, 'Should we just write this line right now?'" she recalled. "So I was sitting in the room with my entire family. We both, all of us, including my dad and my mom, they were like, 'What if it was like....' We were all giving ideas. So technically they should have a writing credit, because we all wrote that line right at the end."

Even though the last line is in English, Eilish convinced the flamenco singer to write and record the song mostly in Spanish because of her appreciation for multilingual music.

"I remember when we were writing the song, I remember her saying something about, 'It should be in English.' And I was like, 'No, no, no. It should be in Spanish. It's so beautiful.' And I've always loved music that isn't in English," the "Therefore I Am" singer told Lowe. "I like tons of music from languages I don't even speak. ... I've been really intrigued by it pretty much my whole life. There's so many Russian songs I like, and Spanish, and French."

Watch Eilish's Apple Music interview below.