We absolutely loved the retro inspired manicure she showed off at The Secret Garden Party last month and last weekend's V Festival inspired nail art has got us itching to expand our nail polish collection!
Of course, Instagram obsessed Mills took to to the picture sharing website on Saturday morning to share a snap of her metallic mani.
Que our excitement when we learned that celebrity nail art maestro Stephanie Staunton AKA Stephie Nails was behind the stunning but easy peasy look - and she used an array of totally affordable high-street lacquers to beautify Millie's digits!
For the chic nude base, Steph looked to Morgan Taylor's nail polish in 'New Romance', £11 after layering the the bare nail with a base coat for maximum staying power.
For a seamless finish, paint a single line down the centre of your nail and then another on each side. One coat looks super-girly but two will most certainly up the glam factor!
Next, Steph took a leaf out of Beyonce's book of beauty triumphs and adorned Millie's nails with lashings of geometric lines, but believe us when we say the look couldn't be simpler to recreate!
Nail guru Steph opted for the Morgan Taylor 'Chrome' and 'Give Me Gold' hues, both a pocket-friendly £11 each, to layer the angular lines over the classic nude tone.
"With a thin nail art brush draw random lines in your chosen colour then work outwards from them," she said. 'Keep adding as you go! Metallics are huge this summer so you'll be bang on trend."
With years of experience and a whole hoard of celeb clients under her belt, it's only fair that Steph shares a few top tips with us! She recommends using a dotting tool or even a humble cocktail stick - yep, really - to create teeny-tiny dots and shapes with minimum effort and virtually zero clean-up.
Once you've got creative, be sure to veil your eye-popping mani with the Nails Inc Kensington Caviar Top Coat, £15 to make sure the pattern doesn't budge or chip.
Et voila! Summer-ready nails sans the fuss.