Back in 2011 when A-listers across the globe started showing off rainbow hair colours, we figured the trend would stick out the summer and then drop off the radar.
But it's still going strong - with the likes of Demi Lovato (who's just shown off a new blue fade-out hue) and Rita Ora the latest to dabble in the dye.
Our advice? If you're new to the trend try a warm, red-based colour rather than a cold one. Blue fades quickly into green on lighter hair colours and can be hard to shift while pinks, purples and reds fade into much more manageable peachy-lilac tones that look better as they develop.
Get some more colour inspiration from the celebs who have trialled the trend so far…
