Katy Perry has launched a foul-mouthed tirade on a former heroine who treated her badly when she first arrived in Los Angeles desperate for music success.
The singer isn't naming names, but she hopes the target of her new Rolling Stone magazine rant reads the piece  and realizes what a terrible person she was.
Perry tells the publication, "I remember coming to L.A. for the first time and meeting Gwen Stefani and how gracious and wonderful she was, and then meeting another favorite artist of mine and what a c**t she was.
"It ruined my dreams of that person, the c**t, and I will always be a fan of the person who was gracious."
And Perry admits the encounter made her realize how important it is to be pleasant and grateful when meeting fans - no matter how she feels.