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Katy Perry's single "Roar" is all about self-empowerment, but according to the singer, the lyrics of the song were a hard lesson that she had to learn.

Speaking to InStyle UK, Perry, 28, said that the song is "all about me finding the strength to stand up for myself and to myself."

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She added that "when you're a kid there are a lot of bullies in the playground, then you grow up and people aren't so outwardly mean, but you find yourself being your [own] biggest bully in the way of your own success, personally and professionally."

Perry, who reunited with beau John Mayer this summer, continued to explain that she now has more confidence than ever.

"I've also been through a big change in my life in the past year," she said. "This time last year I was very unbalanced; professionally I was at the height of my career, and personally I was very immature."

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The "Fireworks" singer said that over the past year she's read incredible books to help her psychological state and even did therapy.

Perry also revealed the inspiration behind her new fragrance, Killer Queen: It's a song by Freddie Mercury, which she said is "about a woman that is strong and fun, that doesn't care too much about outside perception."

Sounds like she's talking about her new self.