"I've been wanting it blonde for a while," began Billie, 19. "I don't know what came over me. I saw a fan edit when I had green hair. It was like me, with whatever hair color I had and they just edited blonde hair on me and I was like, 'Ah! It's so sick! I want it!'"
"So I kind of thought of it as a dream. I didn't think it was going to happen because my hair has been through so much," she continued. "I thought I would burn it all off if I tried, but I did it!"
The Grammy winner -- who debuted her new blonde 'do back in March -- said it took "about six weeks" to go from neon green-and-black hair to platinum blonde. During the transition, Billie wore a wig.
"It's very hard," she recalled to Ellen. "It was a lot. We started in January -- I think January 16th was the first day -- and then it was like two weeks of nothing like healing, letting my hair kind of like take it in and digest and recover. And then again and then two more weeks and then again and then a week. Oh my God, it took a long time."
When Ellen joked if her hair is now "healthy" and "not falling out" when she brushes it, Billie admitted, "Well, I got to say it's been falling out when I brush it for years."
Also during her chat with Ellen, Billie opened up about her upcoming second album, "Happier Than Ever," which will be released on July 30.
"Everything's new. It's a whole new era," she said. "I'm so excited. I can't tell you. It's the most proud I've ever been of anything I've created and I really can't wait for the world to hear it."
Waiting for your permission to load the Instagram Media.