President Joe Biden revealed that Queen Elizabeth II asked him about Russian President Vladimir Putin and Chinese President Xi Jinping while drinking their tea at Windsor Castle on Sunday, June 13.

The Guardian reported that Queen Elizabeth's meeting with the U.S. president lasted for 45 minutes, adding that the British monarch rarely gives comments regarding political discussions.

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Joe Biden Reveals Queen Elizabeth's Political Comments

The revelation happened when President Joe Biden gave a brief statement with White House reporters regarding his meeting with Queen Elizabeth.

"We had a long talk, she was very generous," Biden told the White House reporters on the tarmac at Heathrow airport on Sunday evening. 

Joe Biden also praised Queen Elizabeth, saying that she reminded him of his mother. First Lady Jill Biden joined Biden during their tea that happened in the quadrangle of the Windsor Castle, which was the home to the royal family for nearly 1,000 years.

Apart from his praises, the president also said the Queen inquired about the two leaders he was about to meet.

"She wanted to know about the two leaders that I - the one I'm about to meet with, Mr. Putin, and she wanted to know about Xi Jinping," Biden said.

However, Joe Biden breached a British protocol with what he just said with the reporters because those who speak to Queen Elizabeth on other occasions are not allowed to reveal what they talked about, especially about political matters. 

This was done to prevent Queen Elizabeth from embarrassment because, as head of the state, the monarch does not publicly comment on political matters.

Moreover, The Guardian pointed out that the contents of the weekly audiences with the British prime minister of the day are kept confidential.

"I wish we could stay longer maybe we could hold the cars up a minute, and stuff," said Biden, who invited Queen Elizabeth to the White House. 

It can be remembered that the British monarch first visited the White House in October 1957 when Dwight Eisenhower was the president of the country. The Queen stayed for four days in the U.S. at that time.

Joe Biden's Other Protocol Breach During Meeting with Queen Elizabeth

Apart from revealing some details about his meeting with the Queen, Joe Biden allegedly breached another protocol when he did not remove his sunglasses when he met the British monarch. 

A former butler to Prince Charles and Camilla, the Duchess of Cornwall, confirmed with Newsweek that the President should have removed the sunglasses when he greeted Queen Elizabeth.

"It's fine for Biden to have had sunglasses on but he should have removed them when he actually met the Queen," said former butler Grant Harold. 

Harold also pointed out that sunglasses or any accessories like that shout be removed when meeting the Queen.

"It doesn't matter who you are, even royals remove sunglasses when they meet royals," said Harold.

Joe Biden, accompanied by his wife, marks the thirteenth holder of the office that met Queen Elizabeth. He was scheduled to go to Brussels for his next trip.

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WATCH: 'She Reminded Me of My Mother': Biden on Meeting With The Queen - From Guardian News