Katy Perry is american singer, actress and the author of her oun songs. Her real name is Kathreen Elizabet Hudson. Noone in her family didn't call her Katy. They called her Kate. But she liked name Katy and made her alias like Katy Hudson. With this name she made her first albom. But then she thought than people will mix her up with actress Kate Hudson. And she took her mother's maiden name Perry. My favourite her songs are Roar, Hot n Cold, Box, Firework, Part of me and E.T.