Kate Middleton dazzles in Princess Diana's tiara at Buckingham Palace

Kate Middleton was every bit the dazzling Duchess as she joined Prince William for the Queen's Diplomatic Reception yesterday.

The glittering event takes place every December and is attended by foreign ambassadors and other dignitaries based in the UK, reflecting the importance of the monarch’s international relations.

However, all eyes were on the Duchess of Cambridge as she attended the annual white-tie event wearing the Lover’s Knot tiara previously owned by Princess Diana.

Also known as the Cambridge Lover's Knot tiara, the intricate headpiece was first owned by Queen Mary in the early 1900s and was gifted to Princess Diana in 1981.

Stealing the show as she arrived, Kate was all smiles in a regal long-sleeve navy velvet Alexander McQueen gown. 

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The royal mum-of-three paired her stunning headpiece with diamond earrings and the Nizam of Hyderabad necklace, which was designed by Cartier and gifted to Queen Elizabeth II for her wedding.

To finish off her eye-catching look Kate also donned a blue sash for the evening - symbolising her appointment as Dame Grand Cross of the Royal Victorian Order (GCVO), an honour she received from Her Majesty in April.

Kate was joined by Prince William who looked dapper in a coat and tails, with a white bow tie.

Prince Charles and the Camilla, the Duchess of Cornwall were also in attendance, however, Prince Harry and Meghan Markle were noticeably absent from the reception.