Katy Perry went all Hi-C Ecto Cooler for spring!
The "Dark Horse" songstress debuted her new hair hue on Instagram.
"SLIME GREEN FOR SPRING by my bb's @neeenaboo & @brantmayfield at the @mcmillansalon," she captioned the pic.
Hey, we're not exactly surprised she went for the drastic color change -- because these photos prove the starlet takes her Roy G. Biv education very seriously.
Scroll through to see Katy don every color of the rainbow!