Sometimes I write a song and I'm down with it but I'm like yeah, whatever, and then everybody loves it and then it blows up. I'm like: "Okay! I didn't see that coming."

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.

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

I think I've learnt a lot about bullying and how to deal with bullying and how to get over that and to just be yourself and forget the haters.

I love writing with Adam Lambert. He's really funny and very fun, he's a great friend.

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.

In my head, I wanted to be Madonna, but the music I was writing on paper was not what you'd choreograph dancers in costumes to. It was more coffee-house stuff.