Billie Eilish opened up about her greatest core memory.

In a recent interview with Apple Music, the Bad Guy hitmaker revealed that hearing her fans sing The Greatest, a single from her 2024 album Hit Me Hard and Soft, at her concerts gave her a sense of accomplishment.

Sharing a moment from one of her concerts, Eilish, 22, recalled taking out one of her in-ears and being stunned to hear a “giant arena filled with people singing it [The Greatest].”

“They were singing every other song too, but something about hearing [The Greatest] song that has this meaning for me and this memory for me, and also like the memory of us making it and what it gave us in our kind of creative spirit,” she continued. “And just hearing that crowd sing it, it really made me like, have, you know, in front of me proof.”

“And that is something that I hold so close to me. And every time I get a chance to really see how what I do or whatever impacts people in real-time, that’s the stuff,” the Lovely chart-topper added.

Additionally, before performing The Greatest song live to a sea of fans at her concerts, Eilish performed it for the first time in June during her guest appearance on The Stephen Colbert Show.