The Duchess of Cambridge has been appointed to the highest female rank in the Royal Victorian Order, as the Queen bestows the gift in recognition of her services to the crown.
The Duchess has been awarded the new honour for "services to the Sovereign", announced by Buckingham Palace as she celebrated her eighth wedding anniversary with the Duke today.
It will be seen by admirers of the Royal Family as the ultimate seal of approval for the Duchess, as the Cambridges aim to increase their work in support of the Queen in preparation for the future.
She joined the Duchess of Cornwall, who received the honour on her seventh wedding anniversary in 2012, and Countess of Wessex, who received it after a decade of marriage in 2010, in the ranks of GCVO.
The announcement was made in time for the Queen's service of the Royal Victorian Order on May 3, which will take place in St George's Chapel at Windsor Castle.
A palace source said the Duchess is "honoured and looking forward to continuing to work on behalf of Her Majesty going forward".
Awards under the Royal Victorian Order are made personally by the Queen, without advice from government, for services to the sovereign. The RVO has five classes from member to Knight or Dame Grand Cross, its highest honour, and was founded in April 1896 by Queen Victoria as a way of rewarding personal service.
Eighth wedding anniversaries are traditionally marked with gifts of bronze.
Earlier today, Kensington Palace thanked royal fans for their well wishes as they reminisced over social media photographs of Prince William and Kate Middleton on their wedding day on April 29, 2011.
The Cambridges, who just last week celebrated Louis' first birthday, are getting ready for Charlotte's fourth birthday on Thursday.
The pair, who now have three children - Prince George, Princess Charlotte and Prince Louis - were flatmates after meeting at St Andrews university in Fife, Scotland.
They dated for more than eight years before finally marrying in the grand surrounds of Westminster Abbey in central London in front of 1,900 guests, watched by a global television audience of millions.