The famous couple's marriage crumbled late last year, and Perry released the angst-ridden break-up song just weeks after the British funnyman filed for divorce.
The song's lyrics sparked speculation it had been written in the aftermath of the split, but Perry reveals the track is actually two years old.
However, she has now revealed she was asked to tell fans the track was written more recently, but she didn't want to lie.
Perry tells MTV.com, "I wrote it two years ago, which is funny because everybody is like 'God, it sounds so current.'
"And some people that I work with were like 'You should just say you wrote it a couple of weeks ago.' I'm like 'I'm not a d**chebag, I'm going to tell the truth.'
"I wrote it two years ago when I was writing and recording Teenage Dream, (but) it didn't feel right on the record."