The Duchess of Cambridge received the Ballon Bleu de Cartier watch for her third wedding anniversary in 2014. {retailing at £4,950 for the steel model} The watch is famously set with a tiny sapphire, a perfect match for her engagement ring.
The Cartier brand has a special significance to Prince William whose late mother always wore a Cartier watch, and gave him a specially-engraved timepiece for one of his birthdays when he was younger.
If you want Cartier to make you feel like a princess you have your pick of models from around £3,000 to the breathtaking Tank Cintree at £87,000.