Halsey admits she felt "jealous" of Britney Spears before sampling her song.
The 29-year-old singer sampled Britney's hit Lucky, in her song of the same name.
Now she's told how the original song, made in 2000, was "stuck in her head" while she was receiving treatment for her T-cell lymphoproliferative disorder diagnosis in 2022.
"I have this weird coping mechanism where, if I'm not dealing with something internally, I'll catch myself singing a song that relates to it," she told Paper.
"I would lay there, attached to a pump, like 'I'm so lucky, I'm a star.' It was facetious, and then I was in the studio, and was singing it under my breath, and went, 'Wait, let's do this. Has anyone done this? This has been done, right? Why hasn't this been done? There's no way I'm actually going to interpolate this Britney Spears' song in this major way.'"
There was initial controversy over the sample, where a message was posted on Britney's social media, saying, "I'm speaking with my lawyers today to see what can be done on this matter. It feels illegal and downright cruel." However, a few hours later, Britney wrote, "Fake news !!! That was not me on my phone !!! I love Halsey and that's why I deleted it !!!'
Halsey went on to reveal how she's always looked up to Britney.
"Obviously I will never know what it's like to reach the magnitude and the monolith of fame and exposure and lack of autonomy that she's experienced in her career," she said. "I will never know that, but in a way, there are some parallels. She was the first pop star I fell in love with and I knew everything about her, and I was in love with her and I worshipped her. I was jealous of her. I thought she had the perfect life, as did most of us at the time, and I've always, through every stage of her career, really rooted for her."