Prince Charles and Queen Elizabeth II
Queen Elizabeth II and Prince Charles pose with officers during an official visit to the Household Cavalry Mounted Regiment at Hyde Park Barracks on October 24, 2017 in London. Getty Images/Chris Jackson

Queen Elizabeth II infuriated Prince Charles by inviting Princess Diana to a state banquet after their separation.

In 1992, the Prince and Princess of Wales announced that they had decided to part ways. However, a year after, the Queen reportedly shocked the future king when she invited Princess Diana to join them in a state banquet she hosted at Buckingham Palace for President Mario Soares of Portugal.

The monarch decided to extend an invite to her daughter-in-law but didn’t tell any other member of the royal family. Thus, when Princess Diana walked in the royal ranks, Princess Anne, Queen Mother and especially Prince Charles “could scarcely believe their eyes and were furious,”

According to Richard Kay and Geoffrey Levy, the Queen invited Princess Diana to the event for a reason — she was hoping that Princess Diana and Prince Charles could still rekindle their romance.

“It was because, despite the public mood being against Prince Charles, and the terrible differences between the couple, the Queen still clung to a distant — some are bound to say naive — hope that there could be a reconciliation,” they wrote.

Kay and Levy also pointed out how the Queen invited Princess Diana to Sandringham for Christmas in the same year. At the time, Princess Diana and Prince Charles had been separated for a year, but Her Majesty still invited the princess to Balmoral.

Princess Diana reportedly stayed overnight and joined them to church. However, she left before Christmas lunch. Servants recalled that the atmosphere lightened following her departure. An aide also revealed that “the Queen feared Diana might do ‘something stupid’ to attract attention.”

However, royal correspondent Ross Benson had another story about the state banquet. In his book “Charles: The Untold Story,” he wrote that Princess Diana suddenly phoned the Queen and informed her that she would be attending the banquet. At the time, the Princess of Wales was banned from every royal occasion unless the Queen allows her presence, but the monarch didn’t enforce the ban because she was frightened of Princess Diana.

“The Queen was frightened of the influence that Diana exerted over her sons, William and Harry,” Benson wrote. “And most of all frightened over the future which she senses belongs to Diana. That is why the Queen shied away from telling Diana that she would be unwelcome at the State banquet.”