Katy Perry (née Katheryn Hudson ... including "California Girls," "E.T." and "Firework." She has released five studio albums which have culminated in 50 billion streams and over 48 million ...

Baby, Katy Perry is a firework. And as the singer—mom to 4-year-old Daisy with fiancé Orlando Bloom—turns the big 4-0, allow this look back at her fashion evolution to show you what she's worth.