Duchess of Cambridge Kate Middleton was the fortunate royal to wear Queen Elizabeth’s most expensive jewellery, she was gifted at the time of her wedding in 1947. Nizam of Hyderabad had gifted Queen Elizabeth II a diamond necklace, currently worth £70 million, on her wedding. This diamond necklace is the most expensive piece of jewels from the Queen’s collection. According to the Express.co.uk, Kate Middleton was the lucky royal to wore this necklace in February 2014 to attend an event at the National Portrait Gallery. The Queen’s most expensive necklace features 50 diamonds and it was made by Cartier in 1935. Kate Middleton, 39 tied the knot to Prince William, the grandson of Queen Elizabeth, on April 29, 2011.