She gave us a fair warning about this, so we shouldn't be that surprised!

On Monday Katy Perry debuted her new hair on Instagram and wrote, "SLIME GREEN FOR SPRING by my bb's @neeenaboo & @brantmayfield at the @mcmillansalon."

Last month Katy attended the Museum of Contemporary Art's 35th Anniversary Gala and she told E! News, "I've wanted to go slime green for a long time. It's spring time and I think it's time to freshen up my look. I'm really excited about slime green, but I hope my hair doesn't fall out. I kind of cut my bangs in haste and now I want them gone."

All we have to say is thank goodness she didn't dye her whole head green! Maybe she'll bring the blue back next?