After 70 years of marriage, Queen Elizabeth handed her husband, Prince Philip, a very special honor.
The announcement comes as their closest relatives and friends prepare to toast the couple at a dinner party at Windsor Castle.
Bells rang from Westminster Abbey for more than three hours to mark the couple's milestone anniversary.
Queen Elizabeth II and the Duke of Edinburgh were married on November 20, 1947 just two years after the end of the Second World War.
In their 65 years together, the couple have fulfilled countless royal duties, welcomed four children, eight grandchildren, and four great grandchildren.
For their golden anniversary 20 years ago, the Queen made her famous statement that Philip has been her "strength and stay."
"He is someone who doesn't take easily to compliments but he has, quite simply, been my strength and stay all these years, and I, and his whole family, and this and many other countries, owe him a debt greater than he would ever claim, or we shall ever know," she said.
Previous royal couples have had long-lasting marriages, but Queen Elizabeth is the first monarch to ever reach a platinum anniversary.
As an anniversary gift, the 91-year-old monarch made Prince Philip a knight.
To commemorate their long-standing union, the Queen presented the 96-year-old with the Knight Grand Cross of the Royal Victorian Order. This particular honor is given by the monarch to recognize individuals who have given distinguished personal service to her.
This is key recognition to the man who has walked a few steps behind her royal highness since she became the Queen at the age of 25.
Philip is also a Knight of the Most Noble Order of the Garter, which is the most ancient order of chivalry in Britain.
He also has several other honors and awards, many reflecting his service across the Commonwealth.
His recognition includes, Knight of the Most Ancient and Most Noble Order of the Thistle, The Order of Merit, Knight Grand Cross of the Most Excellent Order of the British Empire, The Order of New Zealand, Queen's Service Order (New Zealand); Knight, Order of Australia; Grand Companion of the Order of Logoghu (Papua New Guinea); Companion, Order of Canada and Commander, Order of Military Merit (Canada).