Billie Eilish's life is "better" when she's being authentic to herself.

The chart-topping singer thought she really "found" herself as a teenager - but she now recognises that she's constantly changing and learning about the world around her.

Billie, 21, told Allure magazine: "When I was 17, I was like, I found it. I found the person I am, forever. This is how I’m going to do it. I found all the ways! These are my boundaries. These are the things that make me happy, and this is my recipe for how I’m going to make music and be happy.

"Then I grew up a little, and suddenly life was like, 'These aren’t going to work. You've got to change. You're not that person anymore.'

"But the more I think about being myself, the better my life is. The more I am myself, the better my life is."

Billie feels proud that she and her brother Finneas have managed to follow their own path in the music business.

The award-wining star was always determined to do things her way and Billie thinks her success justifies that approach.

She said: "I have to give credit to the person I’ve always been - I did not give a f*** at all.

"Between being a 14-year-old girl, and Finneas being a 17-year-old boy, and us making these little songs - we had to be very clear we weren’t going to just do what anybody said. People could have done crazy s***, and I didn’t let them.

"It was many, many years of having to convince a room full of people that I was going to do what I knew was right for me. I had ideas; I had plans."