People are saying Prince William bought Kate this ring

Last week, the Queen hosted a reception at Buckingham Palace for the Diplomatic Corps, and Kate Middleton made headlines by wearing one of Princess Diana's most iconic tiaras.

But another, slightly less conspicuous piece of jewellery caught royal fans' eyes, namely a rather large diamond ring she wore on her right ring finger.

The reason people are talking about it, is that unlike the rest of the pieces she wore, which have been or are part of the royal collection, the origin of the ring is a bit of a mystery.

So naturally, some have concluded that it may simply have been a gift from Kate's husband, Prince William, perhaps on the occasion of their last anniversary, or her birthday in January. In any case, it's the first time she has been photographed wearing it.

The Duchess also wore the Nizam of Hyderabad necklace and matching chandelier earrings. The set belongs to Queen Elizabeth II and was a gift on her wedding day to Prince Philip in 1947 from the last Nizam of Hyderabad, Mir Osman Ali Khan.

She also wore Princess Diana's Cambridge tiara, which also belongs to the Queen, as well as her sapphire and diamond engagement ring, which belonged to the late Princess of Wales and was given to Prince William upon her passing.