The photo caused a huge discussion online, because it showed Billie wearing significantly more form-fitting clothes than she usually does in public.
The "Bad Guy" singer has explained in the past that she wears oversize clothes intentionally so people can't see and have opinions on her body.
"I never want the world to know everything about me," Billie said in an interview with Calvin Klein in 2019. "I mean, that's why I wear big baggy clothes: Nobody can have an opinion, because they haven't seen what's underneath."
She later reiterated her comments in an interview with Vogue Australia, explaining: "I want layers and layers and layers and I want to be mysterious. You don't know what's underneath and you don't know what's on top. I don't want to give anyone the excuse of judging."