When I write for myself, I just get to be myself.

I got called to write for Aerosmith, nothing ever came of it, but I ended up spending the day with Steven Tyler and going to his house and we sat down at the piano, just me and him, and he sang for me and played, then he asked me to sing for him, and then we sang harmony together. That was just a big moment where it was like 'oh my god, my life is crazy!' It was really cool.

Every time I work with Dr. Luke I learn something new. He's kind of like the Andy Warhol of pop music, where he mass produces his art but it always still has heart and always still has an emotional thread to it. I think he's really a genius and I'm so lucky to have gotten to work with him.

I've always felt my spirit animal was a Tiger, so it's funny that now in 'Roar' with Katy Perry - which is a song we write together - there's the line: "I got the eye of the Tiger..." So I feel like there's a little bit of me in there.

It's nice to really have the freedom to write what I want.

I think the difference between a good song and a great song is... honestly, I think the lyrics, because if you have a really solid melody and solid track and everything is there but then the lyric is just okay, then you've got a good song.

It's really liberating and fun to be writing stuff for myself, and really have the freedom to say what I want to say and not really have to think about what somebody else is going to say or have to edit myself to speak from someone else's vision.