Sick of your standard hair shade and want to spice it up for spring? Look no further than Katy Perry, who just dyed her locks slime green. KP has been all about dip-dye and kooky coloring for years, but this hue may just be our fave yet — it's totally giving us badass Dark Horse vibes. Oh, and she isn't the only A-list babe to switch her signature style this week: K-Stew has gone tangerine orange for a new movie role. See? Now's the time to have some hair color fun! YOLO, right?