The mum-of-three tweeted a snap of her new mermaid mani this morning (17 July), courtesy of nail technician Sophy Robson.
And it looks like Lily is a fan of the 'go big or go home' approach, opting for a traffic-stopping shape, vibrant duo-chrome tips and a hit of nail art. Phew!
Get her look (if you dare!) with our guide:
1) If you're lucky enough to have gorgeously long talons, start by filing them into a point (try using the Champneys Glass Nail File, £10, for a clean finish).
Make sure you only file in one direction to keep your pointers in tip-top shape. And if you don't have long nails, fake it with some falsies!
2) Paint each nail with a clear base coat (such as 2true Nail Care Base Coat & Ridgefiller, £1.99).
Once dry, grab your fave duo-chrome nail polish (Models Own Nail Paint in Aqua Violet, £5, is a dead ringer for Lily's shade) and carefully draw two lines diagonally towards the tip of each nail, ending in a point. Repeat until your polish looks opaque, but remember to leave your ring finger bare.
3) Now for your accent finger! Start by coating your nail with a lilac-pink polish, such as Orly Nail Polish in Lollipop, £10.25. Once dry, go wild with your nail art - make like Lily with a dazzling diamond, or go for something more fool-proof such as cute hearts or easy-peasy polka dots.
Try using Nail Art Rock Chic Pens Set, £10, or save yourself some pennies by using your own nail polishes with this Nail Art Brush Set, £7 from Topshop.
Now we wonder how these fit in with baby duty?
What do you think of Lily's nails? Let us know by commenting below as the best comment across the site each week wins £50!