Kate, who was dressed in a red shift dress paired with statement earrings, was driven to the family event by William. Sadly, there was no sign of Prince George on the couple's arrival.
Peter Phillips was seen arriving with his wife Autumn while Lady Gabriella Windsor joined her parents Prince Michael of Kent and Princess Michael of Kent. Princess Beatrice, Timothy Taylor, Lady Helen Taylor and their daughter Estella Taylor also joined in the festivities.
On Christmas Eve, William and Kate will attend another family dinner with the Queen at Sandringham in Norfolk. It's thought they will attend a Christmas day church service the next morning followed by lunch with the royals - but the Middletons haven't been invited.
It's nothing personal, it's simply down to space.
"The Queen is fond of Kate and doesn't mean to exclude her family – indeed she has broken many of the old rules for them in the past," a royal insider told the Daily Mail.
"But if all of her children and grandchildren's wives had their families to lunch, there wouldn't be enough room, even at Sandringham House's dining room".
The Middletons won't be completely left out of the royal celebrations, though. According to reports, William and Kate will return to their newly renovated home Anmer Hall for a Christmas dinner with Kate's family later on in the day.
We're sure there'll be enough cake and mulled wine to go round.