Katy Perry's songs are her "lockbox" of secrets.
The 'Firework' singer may not be as obvious when she's singing about her past boyfriends in her tracks as Taylor Swift, but she does use her songwriting as a way of healing her broken heart and working through her emotions.
Katy - who has recently split with John Mayer and was previously married to Russell Brand - said: "Maybe I'm not specific with names, but that's my lockbox where all my secrets go. Writing is like therapy.
"They all [songs] stem from the truth inside of me. I just want songs to be relatable, and to be adopted as someone else's soundtrack."
Katy saved her most risqué song, 'I Kissed a Girl' until she got a big break, because she knew it would be the track to get people talking about her.
She is quoted by Britain's OK! magazine as saying: "I had something to prove, but I knew exactly what I was doing. I knew I had 'Hot N Cold' up my sleeve, and 'Thinking of You' and 'Waking up in Vegas'. Even if those weren't going to chart, I was putting out 'I Kissed a Girl' first so it would open the most doors. It was more risqué than the other ones, but it would get people talking."
VIA: CONTACT MUSIC