Billie Eilish was "super religious" for years.
The 18-year-old singer wasn't raised with strong beliefs but was "incredibly" interested in the subject for a long time until her faith suddenly "completely went away".
Speaking on her 'me & dad radio' podcast with her father Patrick O'Connell, she said: "I don't know if any of you know -- I don't think I've ever talked about it. When I was little, when I was a little kid, I was super religious for no damn reason.
"My family never was religious. I didn't know anyone that was religious. And for some reason, as a little girl, I just was incredibly religious.
"And then at one point, I don't know what happened. It just completely went away."
The shift suddenly made the 'bad guy' singer "almost anti-religious for no reason also", but she learned from her adjustment in her beliefs and thinks her own experiences have made her a much more open-minded person when it comes to faith and religious views.
She continued: "I don't know why that happened. I don't know what made me that way. And then after that period of my life, I've loved the idea of other beliefs.
"And I think people with closed minds, people like me from a couple years ago -- I think that's very pathetic to have a closed mind. It's very lame. I love hearing people's beliefs.
"And I love talking about what people believe in and hearing why they believe in it and what makes them believe in it.
"And especially if I don't agree, because I like to listen and I like to understand. And I think it's really important to be supportive of all beliefs in the world and all opinions and not shoot people down for what they believe in."
Billie is now in a "very neutral" position when it comes to religion.
She said: "I don't, not believe and I don't do believe. I'm in a very neutral position. I'm open to every belief pretty much.
"[I love] the idea that there's a God. So why not? How would I know? I'm not going to say I know I don't, nobody knows."
The 'everything i wanted' singer's father thought it was "pretty marvellous" that she developed her own beliefs without influence from her family.
Patrick said: "From my point of view, as a parent, we did not go to church and we didn't really talk about religion at all. And wasn't in our household very much. And you just ... believed.
"You had all these kind of organised thoughts about the whole thing. And I thought it was pretty marvellous. I didn't object to it. I didn't say you can't believe that."