So Why Is Kate Middleton, The Prudent Princess, Wearing A Cartier Necklace Worth £49K?

She's built a reputation as the Discount Duchess who would rather borrow her mother's highstreet dress for her first public speech than invest in a new frock, but today Kate Middleton chose to wear a stunning necklace worth an eye-watering £49,000. We gasp!

Arriving at the National Portrait Gallery this morning, Kate looked resplendent in a blue Stella McCartney dress blinged up by the necklace featuring three intertwined circles of pink, yellow and white gold. How fancy and utterly perfect for the Olympics-themed event. And so the hunt for the necklace began - is it another highstreet piece, we wondered, or perhaps a bargain from her mega shopping mecca Bicester Village? No, no and no.

Grazia Daily has discovered the accessory is, in fact, Cartier's Trinity necklace which is available on cartier.com for £49,000. Uh-huh, that's FOURTY NINE THOUSAND POUNDS. Considering her notorious 'prudent princess' ways, we're flabbergasted that she'd showcase such a luxury creation, despite it being utterly gorgeous. What's more, the one piece costs £19K more than six months' worth of royal outfits!

As you know, Prince Charles coughed up approximatley £30K for the Duchess' royal wardrobe during the first six months of being a royal, so we find it hard to believe that she would spend such a huge sum on one item.

We contacted Cartier who are as surprised (and understandably delighted) as us, suggesting that the luxe jewellery brand didn't lend it to to her for the special occasion. So was it a gift? Clarence House won't confirm anything except to say, it's a piece of 'private jewellery'.

The investigation continues...