It's all for Coachella, of course…
No longer the preserve of pensioners, grey hair is fast becoming the it shade amongst the fash pack right now, and judging by how good it looks on Jourdan, we might just be persuaded to give it a go ourselves.
But this isn't a full on all-over grey shade: you'll spot hints of icy blue, dark brown and lilac in Jourdan's locks too that keep this look young and fresh.
And, importantly, means she can match her hair to her trainers. This is some dedicated colour-co-oridnation from Ms Dunn.
So what occasion could possibly call for such a drastic hair makeover? Coachella of course! The model is jetting off to LA to soak up some rays and live music, and clearly needed a new (highly Instagrammable) hair 'do to go with her festival wardrobe.
And she's not the only celeb who has dyed their hair a rainbow shade for the festival. Kylie Jenner has ditched her brunette 'do for a bright turquoise shade for the weekend. Sharing a picture on Instagram, the teenager said she was now ready for her 'road trip.'
Julianne Hough has also gone all out for time in the Californina sun, opting for a 'unicorn' candy pink shade.
So it seems that Coachella is going to be a sea of rainbow hair hues this year. So if you're looking or hair colour inspiration, we suggest keeping a close eye on the Coachella Instagram account this weekend…