Ellie Goulding was an "absolute rebel" when she was younger.
The 'Anything Could Happen' singer went through an anti-establishment period in her teens, which informed her darker lyrics in more recent years.
She said: "I guess I was made out to be like a really good role model. Sensible, girly, flowery and blonde - but that wasn't me. I've always been an absolute rebel. When I was in my teen years I had piercings and wore all black.
"I smoked and drank and did what all my mates did around me. I was never a 'sensible one'.
"And my lyrics have always been dark. It's just that [with new album 'Halcyon'], the music is more raw around the edges and varies from song to song."
The 25-year-old singer - who is dating electronic musician Skrillex - has been a hit in the US, but says she had to toughen up her image.
She added: "I've changed the way I look a bit but not intentionally. I've cut my hair. I've got a bit of pink in it and lately I've become a bit monochrome, wearing a lot of black and white.
"There's definitely something switched in me in that I don't like to wear bright colours.
"I instinctively dress a bit tougher because I've spent a lot of time in the US and I realised there was a certain image projected of me here."
Ellie's second album, 'Halcyon' is out now.