Pop star Katy Perry has confessed she fell in love with a female friend as a teenager.

The I Kissed a Girl hitmaker was forced to hide her feelings from her pal at the time, but now insists mystery girl had a huge impact on her life.

She tells France's Entrevue magazine, "When I was 15, I fell in love with a female friend. I thought she was beautiful and wanted to be like her. She had such a crazy impact on my life, but I never told her how I felt."

The singer, who is now dating musician John Mayer, insists she will never rule out having a relationship with a woman, and also reveals her celebrity crush, adding, "I've told my boyfriend that if Scarlett Johansson wanted to go out with me, I'd let her. No problem. Female beauty can be incredibly powerful... Actually, I'm obsessed with beautiful women and their elegance. I like the paradox of appearing innocent and sexy all at once."