Carole Middleton set to join Kate and William for major occasion as royals 'separate' from King

However, according to royal commentator Emily Andrews, the couple hopes to see Carole and Michael Middleton for Christmas dinner this year.

Andrews claimed: “They prefer the informality of a relaxed lunch at nearby Anmer Hall.

“And I understand will do so again this year, with the addition of the Middleton family.”

Once Prince George, 11, Princess Charlotte, nine, and Prince Louis, six, have broken up from school in mid-December, it is understood the Wales family will travel to Norfolk.

Anmer Hall acts as the Waleses' country home.

Traditionally, Christmas for the Royal Family is held at Sandringham House.

On Christmas Eve, there is a black-tie evening where presents are exchanged.

Then on Christmas Day, there is a visit to church in the morning, followed by lunch and the King's speech.

King Charles, 76, has kept to these traditions largely, although Queen Camilla, 77, has also started inviting her children and grandchildren.

Carole and Michael Middleton are understood to have stepped up to support their daughter through her cancer treatment at her home in Windsor.

Andrews continued to write in Woman Magazine: “So a festive, joyous Middleton Christmas with all the trimmings will be just the ticket.

“It’s also likely to include Kate’s sister Pippa, her husband James Matthews and children Arthur, six, Grace, three and Rose, two, along with her brother James Middleton, his wife Alizée and son Inigo, one.”

While the Waleses are not expected to have lunch at Sandringham House, it has been reported that Prince Andrew, 64 and his ex-wife Sarah Ferguson, 65, will be in attendance.

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Despite his current Royal Lodge row with King Charles, the Duke of York is believed to have received an invite for the Sandringham festivities.

Andrews wrote: “Charles is still receiving treatment for cancer and so Christmas at the ‘Big House’ may be more muted.

“Friends say that the extended Royal Family who were invited to Sandringham last year - among them Prince Andrew and his family, and ex-wife Sarah Ferguson, are awaiting to see how Charles’ health holds up in the coming weeks, but they hope to all go.”