Kate just revealed her go-to £18 beauty buy to the world

The royal family are, for obvious reasons, notoriously tight-lipped about their beauty regimes.

Usually, the only way we find out about their go-to products is through snippets shared by their hair and make-up artists, or sources that are privy to insider information – but in an unexpected turn of events, Kate herself just revealed one of her favourite beauty buys for all of the world to see.

Kate Middleton Clarins
Getty Images

During an appearance at Wimbledon, where she sat on court 14 to watch Harriet Dart vs Christina McHale, the Duchess of Cambridge was pictured holding a tube of Clarins Instant Light Natural Lip Perfector, a sheer hydrating gel which gives lips a hint of shimmer and colour while nourishing and protecting them too.

It comes in a range of shades, but Kate appeared to be wearing 01 Rose Shimmer, a warm, rich pink that worked perfectly with the rest of her natural make-up look.

Kate Middleton Clarins
Getty Images

The choice may come as a surprise to some followers of the mum-of-three, who has long been known as a worshiper at the altar of Bobbi Brown, and in particular, its semi-matte Lip Colour in Sandwash Pink, which has flattering undertones of beige.

Kate loves the Bobbi line so much she even applied her own wedding day make-up using only products from the range – after a few lessons from A-list make-up artist Arabella Preston, of course – but now it looks like she’s mixing up her stash with items from other beauty hall favourites.

Kate Middleton ClarinsClarins Instant Light Natural Lip Perfector in 01 Rose Shimmer, £18.50, Debenhams

To the surprise of absolutely no one, the Kate effect has hit, and the balm is already out of stock on Clarins’ own website, and with several other suppliers. However, you can still snap one up at Debenhams, and other department stores like John Lewis & Partners appear to have some available to shop too.

Well, if it’s good enough for a duchess…