Last April, Rosalía was waiting for Billie Eilish to send her vocal contributions for their much-teased collaboration. “I feel like the production, the sound design, is almost done,” she told Variety at the time, “so I just need that Billie maybe sends the vocals and they send me the ideas that they want to add because we are there.”

It might’ve taken a while to finalize, but the vocals were sent. The ideas were added. And now, the finished product is out, complete with a gauzy, skeletal video that matches the mood of the song itself. That song is called “Lo Vas a Olvidar” and it features both Rosalía and Eilish singing in Spanish.

Featuring trademark sparse production from Eilish’s brother/collaborator Finneas, “Lo Vas a Olvidar” finds both featured artists in their respective zones — a dreamlike plane where slight shifts in mood and atmosphere are guided by powerful vocal moments from each.

The tune was first mentioned by Rosalía sometime in 2019, and later that year, she told Billboard that her and Eilish had met in Los Angeles and worked together while sitting at a piano. “When I released ‘Malamente,’ Billie was one of the first huge artists who shared the video. She has been there from the onset,” Rosalía said. “Then, when I was working with Frank Dukes in Los Angeles, Billie and I had a session together, totally independent from her other projects. We wrote with her at the piano. We created a great idea for a song and had a great time.”

Part of that synergy is Eilish singing in Spanish. “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,” Eilish told Zane Lowe today (January 21) after the song dropped. “It’s so beautiful.”

“Lo Vas a Olvidar” will be featured on the soundtrack to HBO’s hit series Euphoria, which returns for its second season later this year. Check it out above.