In real life I'm pretty easy going and pretty chill, I'm not the party girl who will go wild and crazy necessarily.

When I go and write with other artists - a lot of the time it's with them - it's like a therapy session almost. I ask them what they're listening to and what they're going through and what their influences are and I try to get inside of their head and step into their shoes for a second.

I've been close friends with Katy since teenagers, before she was Katy Perry. She's always been a great resource for me to pull from and watch - from her choice of how public she wants to be about her personal life on down. I also watched her develop from the coffee-house singer-songwriter I knew to her be to playing arenas and killing it.

Obviously I love writing with Katy [Pery], I feel like we're the same person when we write together. Even though we fight a lot, we fight over every line and we pull each other's hair and we cat-fight all the time, it's always worth it in the end.

No matter what, I always have expensive designer shoes. It's all about the shoes for me.

It's just funny that anybody would care at all to take apart the words that I write. It's kind of cool!

I had an epiphany where I realised that there are song titles everywhere - in advertising, in conversations with people at the grocery store - and every time I open my mind to that and find titles, I then weave a story around that.