Her bubblegum pink locks were hugely favoured, her mesmerising turquoise tresses too.
Platinum blonde is a fan favourite but it seems a softer, more natural colour is what they love most.
Yes. Katy has shared a sweet snap to her Instagram account in which she is wearing a honey-blonde wig with chunky, tousled tresses that look to be completely natural. And her followers have positively lost their minds.
At last look the image had garnered more 2.5 million likes and close to 37K comments. That's more than when she posted a pic announcing that she and her actor beau Orlando Bloom were engaged.
Maybe it's the sandy shade that flatters her pale complexion or perhaps it's simply seeing their idol looking new and fresh and, dare we say it, sweet? Whatever the reason folk are going nuts for this look on Katy.
Who knows - perhaps that will inspire her to keep it a while? We'd love that, but going by her history, it seems unlikely. Our advice - enjoy it while you can.