Katy Perry dyed her hair black after an attempt to look like Madonna went horribly wrong.The 'Firework' singer has been dying her hair black since she was 15 and Katy - who is naturally blonde - admitted she only turned to the darker hue after a bleaching disaster.Speaking in a video to promote her July Vogue cover, she said: "I've been dying my hair black since I was 15. The whole reason I dye it is that I was 15 and I chopped it all off. I had it bleached blonde like Madonna and it didn't look right so I bought a box of hair dye and dyed it all black and never looked back."Katy also admitted she is insecure about certain aspects of her looks.She said: "My brows and my eyes, I think, are what frame my whole face. I have all right lips and all right cheekbones, but they're no showoffs. If I get my brows and my eyes right, that really sets the whole face."My skin used to be a lot worse than it is so I would use a lot more coverage as I was insecure about my skin."