Spears's style in the "Pretty Girls" video was undeniably over-the-top. She and Iggy Azalea recreated the film "Earth Girls Are Easy" with their '80s Barbie looks, making for the perfect Halloween costume.
What to wear: A long-sleeved leopard-print crop top over a hot pink bra. Grab a pair of ripped patchwork jeans (in the lowest rise you feel comfortable in). Add a silver belt and giant plastic earrings, and don't skimp on the crimps.