Katy Perry has revealed she really did kiss a girl — and liked it.

The 23-year-old old Californian musician’s single I Kissed A Girl has celebrated more than five million worldwide sales.

In an interview with OK! magazine, Perry was asked if she really had kissed a girl.

She replied: “Of course. I think I was 19. I kissed a girl and it was great.”

She said it went no further and she did not write the song about that one experience or a particular person.

She said: “Growing up I did have a friend who, looking back, I think I had an obsessive little crush on her.

“I never kissed her but she was very beautiful and she was like a ballerina and I wanted to copy everything she did. But I think that was kind of the extent of it.”

She said her boyfriend understood the “tongue-in-cheek” aspect of the song.