Queen Elizabeth Invites President Joe Biden to Tea at Windsor Castle: All About Their Upcoming Visit

CHRIS JACKSON/POOL/AFP via Getty Images Queen Elizabeth

Queen Elizabeth is preparing to meet her 13th serving U.S. President!

Early on Thursday, Buckingham Palace confirmed more details about President Joe Biden and First Lady Dr. Jill Biden's visit to Windsor Castle on Sunday.

The Bidens will be welcomed at the dais in the Quadrangle of the castle, and a Guard of Honor formed of the Queen's Company First Battalion Grenadier Guards will give a royal salute. The U.S. national anthem will be played, the palace confirmed.

NEIL HALL/POOL/EPA-EFE/Shutterstock President Biden arriving in the UK on Wednesday

The President will then accompany the Officer Commanding, Major James Taylor, and Major General Christopher Ghika, to inspect the Guard of Honor, before returning to the dais to watch the military march past alongside the Queen, 95, and the First Lady, the palace said.

The Queen and her VIP guests will then have tea inside the 1,000-year-old castle.

It comes a day after the Queen will enjoy her official birthday parade, Trooping the Colour, in the same quadrangle at the castle. The visit by the Bidens will be the most high-profile engagement for the Queen since the death of her beloved husband Prince Philip, aged 99, in April. Poignantly, he would have celebrated his 100th birthday today - and she is spending the day quietly and privately, a source has told PEOPLE.

"She has an enormous amount of family support for her and will also take comfort from the enormity of the support from all over the world," Charles Anson, former press secretary to the Queen, told PEOPLE.

Late on Wednesday it was announced that Philip was being remembered and celebrated with a commemorative rose, that had been especially bred for his centenary. It was presented to the Queen last week and she has had it planted in part of the garden that he designed.

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Three years ago, the Queen welcomed President Donald Trump to Windsor Castle and then retired for tea, just as she will with President Biden. President Barack Obama and First Lady Michelle Obama were also entertained at the castle two years before that.

Chris Jackson/Getty Images

The Bidens arrived in the U.K. on Wednesday. The focus of their trip is the G-7 meeting taking place over the weekend. The economic summit marks the first face-to-face gathering of leaders representing the G-7 (Canada, Germany, France, Italy, Japan, the U.K. and the U.S.) in two years.

This year's events will focus on a "build back better" theme amid the COVID-19 pandemic, according to organizers.