Kate Middleton wears a Zara necklace as she chats to guests

Kate Middleton made headlines when she wore a faux-diamond necklace from Zara last year

Kate Middleton, the Duchess of Cambridge is truly a high-street Queen at heart. The royal mum-of-one, who turns 32 today, was spotted shopping around her old haunt of Chelsea on Tuesday, popping in to the Peter Jones department store on Sloane Square. The Duchess, who wears every designer from Zara to Alexander McQueen, and even some relatively unknown brands in between, was reportedly picking up some homeward supplies for her new Kensington Palace apartment.

Reports suggest that Kate was shopping with her mum Carole and her sister Pippa, and was wearing a light blue coat. Fellow shopper Louisa Smith spoke to People.com after seeing the famous royal at the cashier section. She told the site: 'You wouldn't have known it was Kate Middleton. The shop is always quite calm anyway, and there wasn't a great deal of people around.'

She added: 'In fact, it was only when I did a double-take that I realised it was her.'

We're so jealous right now.

Kate Middleton wears Alice Temperley to a film premiere

Louisa says: 'She was absolutely beautiful. She has a very magnetic energy about her. She looked absolutely stunning. It was nice to see her doing ordinary stuff.'

Kate is celebrating her 32nd birthday today with a quiet celebration at her home. Kensington Palace has confirmed that she won't be out and about in London for her big day, but instead, 'The Duchess of Cambridge is spending her birthday privately,' the spokesperson said.

However she's spending it, she has plenty to celebrate. The Duchess is looking on to an exciting year where she'll visit New Zealand and Australia in April with Prince William and Prince George. We wonder if there'll be a few high street hits in her Oz wardrobe...

By Rebecca Martin

Got a tablet? You can now download InStyle magazine straight to your iPad, Kindle (just search the store for 'instyle magazine'), Nook or Google Nexus.