Perry's 'emotional filing cabinet'
Katy Perry has said she wanted to show she could write songs about more than DJs, dancing and getting drunk with her new album.
The singer, who made her name with danceable, playful pop tunes, has released her second album Teenage Dream.
She said of the new release: "Sure, I wanted to make a record with more tempo, but I didn't want that to mean that I had to write about just DJs and dancing and getting drunk."
Katy added: "I need a soundtrack for all the rest of my emotions, and that's what I really wanted to provide with this.
"If you had all that 'Last Friday Night' as the subject matter for every single song, it would be like, 'You're soulless, your spineless. Is there anything else to your world?'"
She said of the new album: "This record is going to kind of solidify the fact that I have something different to offer, a different perspective.
"This record could be more important than the first. It shows that it wasn't a lottery, it shows that it wasn't luck - it just shows that it's good."
One of the songs on the album, Circle The Drain, sees Katy lash out at a lover who is destroying himself and their relationship with drugs.
Katy, who rose to fame two years ago, said: "It was difficult to write it because it's not where I am now, but it was a feeling that I had stored away a long time ago, in my emotional filing cabinet."