Billie Eilish has no idea about the cost of basics

Billie Eilish for Vanity Fair magazine

Ahead of the release of the The World's A Little Blurry documentary, out next month on Apple TV+, Billie Eilish gave Vanity Fair an expansive interview touching on everything from the global critical and commercial success of her debut album to what's ahead with impending new music.

"She said: "[The devotion] makes you kind of insane. "To be quite honest with you, I only started wearing baggy clothes because of my body", said the "Therefore I Am" singer.

Billie Eilish has opened up about the "horrible relationship" she once had with her body that involved starving herself and taking diet pills at a young age. "And I'm like, "Nope, this is how I look, you've just never seen it before!'"

Her loved ones were much more anxious, however.

Fans around the globe adore Billie Eilish, but for years she has struggled to love herself. I was really, really glad, mainly, that I am in this place in my life, because if that had happened 3 years ago, when I was in the midst of my awful body relationship-or dancing a ton, 5 years ago, I was not really eating.

Billie Eilish attends the 40th Brit Awards in London.

Eilish recalled barely being a teenager when she tried to take a pill to lose weight.

"I don't know what things cost because I've never been an adult before", she said.

"I thought that I would be the only one dealing with my hatred for my body, but I guess the internet also hates my body". I've had a lot of weird situations-people will kiss me and pick me up, spin me around.

"I dress the way I dress as I don't like to think of you guys - I mean anyone, everyone - judging it, or the size of it", she said. It's Dollars 35. I didn't know that that's expensive. "I ordered 70 [1-ounce] boxes".

In the same interview, she also spoke about the attention that she had received concerning her body - specifically the paparazzi photograph that went viral a year ago of her in a vest and shorts, en route to the beach. Now the pop icon is opening up about the "hatred" she felt for her body growing up and how deeply it impacted her mental health.

Eilish will give a candid glimpse into her life in the forthcoming documentary Billie Eilish: The World's a Little Blurry, which premieres February 26 on Apple TV+.