Billie Eilish, along with her brother Finneas O’Connell, has won the Oscar for best song with What Was I Made For?, which the pair co-wrote for the Barbie movie soundtrack.

Eilish and O’Connell had to defeat a lineup that contained another song from Barbie: I’m Just Ken, written by Mark Ronson and Andrew Wyatt and performed by Ryan Gosling. Other contenders included Wahzhazhe (A Song for My People) from Killers of the Flower Moon, and It Never Went Away from the documentary American Symphony.

A No 1 hit in the UK and Australia, as well as reaching number 14 in the US, What Was I Made For? accompanies a scene in the film in which Barbie, played by Margot Robbie, meets the ghost of her creator Ruth Handler (played by Rhea Perlman). It won best song of the year and best song written for visual media at the Grammy awards in February.

“I feel so incredibly lucky and honoured,” said Eilish, dedicating the award to “everyone affected by the movie and how incredible it was.”

She also thanked her best friend, Zoe, “for playing Barbies with me” as well as two music teachers, one of whom “didn’t like me but you were good at your job”.

Read more about the 2024 Oscars:

• Here’s our news wrap and full list of winners – now read Peter Bradshaw’s verdict
• Al Pacino, British mothers and a codpiece envelope: the real winners and losers of the night
• Relive how the ceremony unfolded with our liveblog and get up to speed with the top viral moments and the best quotes of the night
• Have a gander at how the stars looked on the red carpet and at the show