Prince William, Prince Charles
Pictured: Prince William, Prince Charles arrives next to his father Prince Charles, Prince of Wales as they walk to St. George's Chapel to partake in Garter Day, the 660th Anniversary Service, on June 16, 2008 in Windsor, England. Getty Images/Chris Jackson

Prince William and Prince Charles snubbed Donald Trump a year ago.

On Monday, the U.S. president is set to arrive in the U.K. for an official visit. Donald and Melania Trump are set to meet the royal family including Queen Elizabeth II, Prince Charles, Camilla Parker Bowles, Prince William, Kate Middleton and Prince Harry.

Although this time the Prince of Wales and Duke of Cambridge are open to meeting the politician, they reportedly snubbed him last year. According to a report by The Sunday Times, both Prince Charles and Prince William “refused to attend” last year’s meeting with Trump when he visited the U.K.

“This business of Prince Charles and Prince William not being there for the Trump visit was a snub,” a source told The Sunday Times.

“They simply refused to attend. It's a very, very unusual thing for the Queen to be there on her own. Usually, she is accompanied by somebody. Prince Charles has been substituting for Philip a lot recently.”

The source insisted that if Prince Charles wanted to be there, he could be there because he could go to whatever event he wanted to. The palace addressed the alleged snubbing incident and explained that Prince Charles and Prince William were not expected to accompany Queen Elizabeth II in her meeting with Trump.

In a statement, Buckingham Palace said that the U.S. president was received by Queen Elizabeth II as the Head of State. The arrangement was mutually agreed between the Palace, the U.K. and the U.S. government and there was never a suggestion that other members of the royal family would take part in the said meeting.

Years ago, Trump made several harsh comments about the members of the royal family. Trump once claimed that Prince William and Prince Harry’s mom, Princess Diana, was attracted to him even though the People’s Princess’ friends revealed that he was “stalking her.”

Also, he blamed Middleton for her photo scandal. In 2012, the Duchess of Cambridge was photographed topless during a vacation with Prince William in France. Trump commented on the incident by turning to Twitter where he wrote that Middleton shouldn’t have sunbathed nude, adding that she only had “herself to blame.”