Watch: President Biden, first lady meet Queen Elizabeth II
The Queen has met her 13th US president after she welcomed Joe and Jill Biden to Windsor Castle for tea on Sunday afternoon.
The Queen briefly met the couple on Friday evening in Cornwall as part of a reception the Royal Family held for world leaders, but was able to sit down with them for longer during afternoon tea.
After arriving at the castle, the Bidens were greeted by the Queen on the dais at the Quadrangle where a Guard of Honour assembled.
Biden accompanied the Officer Commanding the Guard of Honour, Major James Taylor, and Major General Christopher Ghika to inspect the Honour Guard, before returning to the dais to watch the military march-past with the Queen and Dr Biden.
He also granted permission for the Guard to continue their duties.
Inspecting a Guard of Honour with a visiting head of state is a job that used to go to the Duke of Edinburgh.
The Queen wore a Stewart Parvin dress in a floral print jacquard in shades of pink, olive and russet, with matching hat by Rachel Trevor-Morgan, and donned white gloves for the occasion.
She had the diamond Jardine star brooch on.
Biden wore a dark suit and was wearing aviator sunglasses when he arrived, though he took these off to inspect the Guard. The first lady, Dr Biden, wore a powder blue suit.
The Queen was formally welcomed by the Grenadier Guards at the castle, with the national anthem, before the Bidens were driven to the Quadrangle..
The band played the US national anthem when the president and the first lady arrived. The Queen was spotted chatting to each of them as they stood either side of her during the small ceremony.
She also made the president laugh at one point, after he had inspected the guard.
After the official welcome, the Queen led the president and the first lady into the castle, introducing them to her lady-in-waiting Dame Annabel Whitehead.
As they walked in, the Queen was heard asking Biden about the G7 summit in Cornwall, saying: "You completed your talks."
He replied: "Yes we did."
The Queen served them tea, along with cake and sandwiches, and the Bidens will likely have an opportunity to meet the royal dogs.
Watch: G7 summit: President Biden and First Lady greeted by Queen as they arrive at Windsor Castle for tea
Ahead of the meeting, the Royal Family shared a picture of Windsor Castle on Twitter, explaining that Biden is the fourth president in recent years to be welcomed there.
However on this visit, the Queen is living at Windsor full time, having moved there before the UK lockdown in March 2020.
Donald Trump, who Biden succeeded, was also received at Windsor in 2018, as protests in London meant it was deemed safer to be away from Buckingham Palace.
On that occasion the Queen joined with him to inspect the guard.
They then had tea in the Oak Room of the castle, with the meeting taking longer than was initially planned, at 50 minutes instead of the scheduled half an hour.
The Bidens were ahead of schedule to meet the Queen on Sunday, and entered the Sovereigns Entrance at 5.18pm. They left the castle at 6.03pm where they boarded the Marine One helicopter.
Dr Biden is to return to the US, and the president will go onto Brussels.
It is believed the visit overran by 10 minutes.
Biden gave waiting reporters at Heathrow some insight into the meeting afterwards, telling them the Queen was "gracious" and "generous" and said she reminded him of his mother.
He said they had spoken about Russian president Vladimir Putin and China’s leader Xi Jinping.
He also said he invited her to the White House and that she had asked what life was like there.
The Queen, 95, has had a busy weekend of engagements, with a packed day on Friday in Cornwall, meeting world leaders at the G7, and attending an event for the Big Lunch.
The Big Lunch scheme aims to unite neighbours and communities and will be a part of her Platinum Jubilee celebrations in 2022.
On Saturday she celebrated her official birthday with the Trooping the Colour parade at Windsor, the second year in a row it has been held there.
The ceremony was still smaller than usual, though bigger than last year, with nearly 300 members of the armed forces, compared with about 85 in 2020.
The Queen also had company as she invited her cousin the Duke of Kent to join her.
Last year she watched alone because of restrictions around household mingling.
The Queen has met all but one US president who has worked during her 69-year reign. She never met Lyndon B Johnson.
Sunday afternoon's meeting is a further sign of her commitment to the office of Head of State, despite her age.
Watch: Joe Biden's meeting with the Queen at Windsor Castle will be 'huge honour' for US president