The Princess of Wales has not been seen in public since attending the royal family's Christmas Day church service at Sandringham with her children.
Kate's absence is notable after Kensington Palace announced today that she had successfully undergone planned abdominal surgery.
Kate held hands with Princess Charlotte and beamed as she walked past well-wishers
Adding a touch of glamor to the festive look, Diana paid a sweet tribute to her mother-in-law by wearing a pair of Princess Diana earrings.
She has worn the dazzling earrings on a number of high-profile occasions.
The Princess of Wales looked effortlessly chic as she attended the Christmas Day church service at Sandringham with Prince William, the King and the rest of the royal family today.
Kate, 41, beamed alongside her children Prince Louis, five, Princess Charlotte, eight, and Prince George, 10, in a blue Alexander McQueen coat and custom Gianvito Rossi 'Glen 85' boots as she headed to the St. Mary Magdalene Church on the Norfolk Estate
Princess Diana's 'The Saudi Suite' set, a wedding gift from Crown Prince Fahd, includes a sapphire watch, earrings, bracelet, ring and necklace.
Diana, who loved sapphires, wore the entire set to a state reception in Brisbane in 1983, but also experimented with each item individually.
The earrings featured detachable sapphire drops, which Diana removed before wearing the resulting chunky stud earrings, each surrounded by ten round diamonds, to mark Harry's birth in 1985.
When William gave them to Kate after their engagement in 2010, she also put her own stamp on them and transformed them into modest earrings.
Kate, who has been known to wear the same clothes in different colors, also owns a green version of the Alexander McQueen coat, which she wore on a trip to Boston.
She paired the look with a festive fascinator, a navy blue turtleneck and a pleated midi skirt.
Hundreds of well-wishers have been queuing since the early hours to catch a glimpse of the royals, and waved excitedly as Charles and Camilla made their way to the church.
Meanwhile, Prince Harry has remained in the US with Meghan and their two children Archie and Lilibet – despite recent hopes of a thaw in relations between King Charles and his youngest son.