King Charles warned of Prince William, Kate Middleton's reaction to his Christmas plan

Prince William and Kate Middleton may react to King Charles III's decision in a surprising way if the monarch's Christmas plan goes against their wish.

The Prince and Princess of Wales, who are at loggerheads with the Sussexes, would express their anger if the 75-year-old monarch prefers Harry and Meghan over them.

There are speculations that Prince Harry and Meghan Markle have expedited efforts to heal the rift with King Charles and the royal family as the Duke wants to spend this year Christmas with his relatives in the UK.

READ MORE: Prince Harry, Meghan Markle speed up efforts to heal rift with royal family before Christmas

It emerged after Harry reportedly called the monarch to wish him 75th birthday earlier this month, ending a six-month stalemate between the father-son duo.

King Charles, according to insiders, is thinking to invite Harry and Meghan to spend Christmas with their children at Sandringham House, where the royal family traditionally stays during the festive period.

However, a source close to William and Kate, has claimed: "Future King William and his wife Kate, the Prince and Princess of Wales, have already discussed Christmas plans with the King," adding that "if anything wrong goes it may spark shocking reaction from the Waleses."

"Prince William may show some leniency towards his brother, and could show his obedience to his father but Kate has made up her mind to not to forgive them after their persistent attacks against her," the source added.

If the King invites Prince Archie and Princess Lilibet's parents, Meghan and Harry, it could cause major upset for William and Kate.