He once described her as his “darling daughter-in-law”, and the mutual love and admiration they have for one another is evident.
With that in mind, it seems the King has made a sweet decision regarding his coronation.
According to the Daily Mail's Richard Eden, Charles has invited Kate's family: her parents Michael and Carole Middleton, and her younger siblings, Pippa and James. Find out eveything you need to know about the Middleton clan in the video below...
“They are the family of our future queen, so it's right that they should be there,” he was told by one of their friends.
It won't be the first time that the Middletons have attended a high-profile royal event.
They have previously been invited to join the family at church in Sandringham and were spotted at the Queen's Platinum Jubilee Party last June.
Carole and Michael also joined senior members of the royal family at the Queen's funeral and committal service in September.
There are just three days to go until King Charles's coronation – and already the first official guest has arrived.
Around 2,300 guests will be present for the historic two-hour ceremony at Westminster Abbey in London.
Royals from around the world will be among the congregation, with many sharing a warm friendship with the British royals, including King Felipe and Queen Letizia of Spain, and Greece's Crown Prince Pavlos.
Of course, the British royal family will be out in force. Key attendees at the service will of course include the Prince and Princess of Wales and their children, Prince George, who has a starring role, Princess Charlotte, and Prince Louis.
Buckingham Palace has also now shared details of the royals who will take part in Big Lunch and Big Help Out events as part of the coronation weekend from 6 to 8 May.
The Duke and Duchess of Edinburgh will be among the royals getting involved in the festivities taking place across the nation, with thousands of people expected to come together for street parties on Sunday.
Meanwhile, the Princess Royal and her husband, Vice Admiral Sir Tim Laurence, will attend a community street party in Swindon, while the King's nieces, Princess Beatrice and Princess Eugenie will attend a big lunch in Windsor.
Members of the royal family will then attend the coronation concert at Windsor Castle on Sunday evening, with Take That, Katy Perry and Lionel Richie among the star-studded line-up.
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