Prince Charles embarrassed Queen Elizabeth II by deliberately snubbing a state dinner.

On Monday, the royals gathered together to join the Queen in the state banquet she hosted for U.S. President Donald Trump and his wife, Melania. Prince Charles, Camilla Parker Bowles, Prince William, Kate Middleton and Prince Harry were in attendance at the event.

However, this wasn’t always the case. There was reportedly a time when the Prince of Wales deliberately snubbed a state dinner by not joining the Queen even though he was expected to be there. The state dinner was for former Chinese President Jiang Zemin on Oct. 20, 1999.

“There absolutely was an expectation that Charles would be there. So Charles would have been the second last to get there,” royal commentator Richard Kay said in the 2017 documentary “The Royal House of Windsor.”

However, when the car arrived and the Queen was getting out they realized that there was a big story to cover because Prince Charles wasn’t there. If he were present, he would have gotten out of the car before the Queen because the monarch is always the last person to arrive.

Kay continued by saying that there was no explanation from the palace. He felt that they were “caught unaware.”

“I think by not attending on this occasion he was not only letting down the monarchy but he was embarrassing his mother,” he added.

Meanwhile, Prince Charles’ former aide Mark Bolland confessed that it was a “deliberate snub.” The palace reportedly denied it, but Prince Charles kept on snubbing future events that the Chinese president attended.

Reports have it that Prince Charles’ action was an act of rebellion since the monarch tried to foster good trading relations with China. Prince Charles was a supporter of Tibet’s claim of independence from China.

According to Kay, a significant figure like the Prince of Wales showing his disapproval on what’s going on in Beijing was “damaging in the extreme.” Some even described him as a “petulant and selfish prince.”

In related news, a photo of Prince Charles looking bored during Queen Elizabeth II’s coronation recently resurfaced. Netizens made fun of it by commenting that up to this time Prince Charles is “still waiting” for his time to reign.

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