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.

I'm a really visual artist, and I love writing treatments for music videos, photo shoots, fashion, and all the visual parts that go along with making an album.

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 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.

Cheating is bad. That's a big mistake I've made, and I've really hurt people. I've never lied about it, though. I've always been honest.

I tend to get a little quirkier and crazier with my lyrics and come from a different angle when I'm writing for myself.

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.