Buckingham Palace had special visitors on Tuesday, Dec. 3, and Queen Elizabeth led the royal family in welcoming her guests like U.S. President Donald Trump, First Lady Melania Trump and the rest of the leaders of NATO, who are attending their annual summit.

Prince Charles, Camilla, the Duchess of Cornwall, and Kate Middleton, the Duchess of Cambridge, were on hand to help the Queen welcome their distinguished NATO guests along with Queen Elizabeth's other children, Prince Edward, and Princess Anne. Missing from the reception, however, were Prince William, the Duke of Cambridge, and the Sussex royals, Prince Harry and Meghan Markle, as well as Prince Andrew, who is Trump's personal friend.

Prince William had to be absent from this reception and let Kate be by herself because he was on a royal trip to the Middle East. Prince Andrew, on the other hand, was not expected at the event after he announced in early November that he would be stepping down from his royal duties due to his ties with the sex offender Jeffrey Epstein.

Prince Harry and Meghan, on the other hand, are reportedly not in London as they are on a six-week holiday. According to the Daily Mail, the Sussex pair quietly spent Thanksgiving with close family members in the United States. Prince Harry and Meghan will stay in America for Christmas as well and will be missing the royal celebrations in Sandringham with Queen Elizabeth.

Meanwhile, Kate sparkled in green during the NATO reception. The Duchess of Cambridge wore an Emilia Wickstead dress as she laughed and talked with some of the officials. The U.S. First Lady also looked vibrant in her yellow and pink Valentino cape while the Queen wore a green and black printed dress. Camilla was the lady in red as she exchanged pleasantries with Melania.

Earlier that afternoon, the Trumps had tea at Clarence House with Prince Charles and Camilla. According to Vanity Fair, the U.S. President kept Prince Charles waiting for at nearly an hour and spent 15 minutes with the next in line to the throne until they had to go to Buckingham to be with Queen Elizabeth.

NATO has 12 founding members and 29 allied countries. Also expected at the summit were U.K. Prime Minister Boris Johnson, Germany's Chancellor Angela Markel, France's President Emmanuel Macron, Canada's Prime Minister Justin Trudeau, and Turkey's Recep Tayyip Erdogan.