We've lost count of the times the popstar has changed her hair colour since she first shot to fame in 2008. She's partial to trying other outlandish beauty trends too. (Remember when she bleached her eyebrows?)
No stranger to vibrant hair colours, Katy has showed off purple, blue, blonde, pink and more recently, lime green locks over the years. As the singer said herself in an interview with E! Magazine, "I hope my hair doesn't fall out." So do we Katy, so do we.
Of all the styles Katy has had, we still think she looks best when she wears her glossy, jet black hair in soft waves.
Flick through Katy's incredible hair transformation below. It's a good'un.