Billie Eilish and Finneas O’Connell made Oscar history by becoming the two youngest two-time winners in Academy Awards history, as they picked up the best song trophy for a second time Sunday night for “What Was I Made For?,” their contribution to the “Barbie” soundtrack.

The pop-star siblings previously won for “No Time to Die,” the title song for the 2022 James Bond film. At 22, Eilish has now become the youngest two-time winner in Oscar history; at 26, O’Connell is believed to be the second youngest dual winner.

Eilish’s acceptance speech was punctuated with nervous laughter, as she thanked director Greta Gerwig. “I’m so grateful for this song and for this movie and the way it made me feel,” she said. “This goes out to everyone who was affected by this movie.” She thanked her school dance and choir teachers (including one “Miss Teague, who didn’t like me but you were good at your job,” which brought a laugh from the Dolby Theatre audience). She also thanked her “best friend Zoe for playing Barbies with me growing up.”

O’Connell added thanks to producer-star Margot Robbie, score composer-producers Mark Ronson and Andrew Wyatt “for making the song with us,” and their parents “forever and ever and ever.”

Backstage after the win, Eilish spoke about an early musical-theater experience, seeing “Matilda” on Broadway at age 12, “sobbing my eyes out and [thinking] I’m a failure, I’m not going to have a career.” Just a decade later, she has two Oscars and nine Grammys.

O’Connell attributed the success of the film to “great storytelling. People went into that movie expecting to see a spectacle, expecting to laugh, and Greta and Margot brought a lot more to it. We went into that movie for the first time to think about writing a song for it, and this was so much more than we thought we were going to see. We were so moved by it.”

Eilish added that “it made a lot of people feel very seen. That can be rare, especially as a woman. I think that really resonated, and traveled the world, feeling seen and heard and understood.”

READ MORE: See all the 2024 Oscar winners here.

“What Was I Made For?” was one of two nominated “Barbie” songs. “I’m Just Ken,” the comic lament sung by Ryan Gosling, was the other (by Ronson and Wyatt, who previously won for “Shallow” in 2018’s “A Star Is Born”).

But while “I’m Just Ken” was performed on-camera in the film, as part of the beachfront battle and elaborate dance number, Eilish’s tender ballad — a melancholy meditation on the complexity of human emotions — added emotional depth to the story and was widely predicted to win. Gerwig called it “Barbie’s heart song.”

Eilish and O’Connell already won the Golden Globe and two Grammys (including song of the year) along with Society of Composers & Lyricists honors for “What Was I Made For?” Further boosting it in the odds was an estimated 633 million streams for the Eilish song, far outpacing the 105 million reported for “I’m Just Ken.”