Billie Eilish likes the taste of blood and "dirty" old coins.
The 'Bad Guy' hitmaker has an iron deficiency and the 17-year-old singer admitted the problem makes unusual items "taste good" to her.
She told the Daily Star newspaper's Wired column: "Because I have an iron deficiency s**t tastes good. Do you guys like the taste of blood?
"Because I like it, I like the taste of blood, I like the taste of pennies, metal, poles and jewellery. Dirty jewellery tastes so good. I used to literally suck on pennies and s**t and I would lick poles! My dumba**."
Meanwhile, Billie recently confessed she is still getting used to the new things she has to "deal" with now she is famous.
She said: "There are so many things I used to have deal with that I don't at all anymore and there are so many things I never used to have to deal with that I do now.
"It's a weird balance between the two. I'm a lot more protective of everything ... Everyone [in the music industry] is ready to tell you what to do. Everyone is ready to be, like, 'You're my creation.' It's weird that the hard thing to do is do what you want to, because everyone wants to make a product."
However, the teenage star explained she goes to see a therapist because she finds it hard to talk to people sometimes due to the unique nature of her career.
She added: "I don't know. People don't like my job. I can't tell anyone about it. Because either it sounds like I'm bragging, or it sounds like I'm being ungrateful. I've started going to therapy, because it's the only person I can talk to."