The royal family's Christmas celebrations are in full swing!

Kate Middleton, Prince Harry and other notable members of the British monarchy were spotted arriving at Queen Elizabeth's annual Christmas lunch at Buckingham Palace on Wednesday, Dec. 16 — but where was Prince William?

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Kate arriving at Buckingham Palace on Wednesday, Dec. 15.

"The Duke had a personal commitment [yesterday] and could not be at the lunch as planned," a source told E! News of William's absence at the event. According to the entertainment news outlet, the Duke of Cambridge, 33, was instead attending a memorial service for the late father of one of his close friends.

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Meanwhile, Kate, also 33, was photographed arriving at the palace in a chauffeured car with her brother-in-law, Harry, 31, and her son, Prince George, 2. It is not known if her daughter, Princess Charlotte, 6 months, was also at the luncheon.

kate middleton and prince harry

Kate, Harry and George (far left) on Wednesday, Dec. 15.

For the special gathering — held each year before the Queen and her husband, Prince Philip, depart for their Christmas vacation at Sandringham estate — the Duchess of Cambridge looked perfectly festive in a cherry-colored coat dress while Harry donned a dapper navy blue suit.