Last month, when Katy Perry performed 'Part of Me' for the first time, some people thought the song was a jab at ex Russell Brand.

"You can keep the diamond ring / It don't mean nothing anyway/ In fact, you can keep everything . . . except for me."

Sounds like it would be a perfect fit for Russell, except Katy now says she wrote the song TWO years ago. Sounds like certain people told her to lie and say it was about him.

"Some people that I work with were like 'You should say you wrote it a couple weeks ago.'  I'm like, 'I'm not a [D-word]. I'm going to tell the truth.'"

"Part of Me" is the lead single from Katy's upcoming "Teenage Dream" expanded re-issue, "The Complete Confection". It comes out March 27th.

Watch Katy Perry Talk About ‘Part Of Me’

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