Prince William and Kate Middleton, Princess of Wales, are returning to a royal family Christmas tradition.

On Sunday, William, Kate and their three children attended the holiday service at Church of St. Mary Magdalene in Norfolk. Prince George, 9, and Princess Charlotte, 7, participated in the holiday service in 2019, but this year marks Prince Louis', 4, debut.

The newly appointed Prince and Princess of Wales joined King Charles III and Camilla, Queen Consort, on Christmas Day. 2022 is the first time the royal family has celebrated the holiday together since the coronavirus pandemic two years ago.

Middleton was seen in a green coat and matching hat as her daughter wore a bright red dress, fitting for Christmas day. William and George wore suits with blue ties and Louis was seen in a blue coat and knee socks. 

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Before the holiday weekend, Middleton had a special message for Queen Elizabeth II at her second annual "Royal Carols: Together at Christmas" event. 

She shared on Instagram, "This year’s service is dedicated to Her Late Majesty Queen Elizabeth II and to all those who are sadly no longer with us. While Christmas will feel very different this year, we can still remember the memories and traditions we shared."

"Take time to slow down and celebrate with family and friends all the wonderful things that make Christmas so special."

The princess was stunning in a sparkly black jacket with gold trim as she shared, "This year, we've invited hundreds of inspiring individuals to the service. Those who showcase the power of connectedness and community values, allowing us to continue Her Majesty's tradition of recognizing and thanking those who have gone above and beyond to support others. Her Majesty leaves with us an incredible legacy and one that has deeply inspired many of us."

Christmas was always very special for the queen, who died at 96 years old in September. The queen often spoke of love, charity and family in her annual Christmas speeches throughout her reign, and she gave an especially personal speech last year, after the death of her husband Prince Philip.

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The monarch shared, "Although it’s a time of great happiness and good cheer for many, Christmas can be hard for those who have lost loved ones. This year, especially, I understand why."

Charles previously announced that he would host Christmas at Sandringham, Queen Elizabeth's estate in Norfolk, continuing the long tradition within the royal family.

Fox News Digital's Cara Haladey contributed to this report

The day after Christmas – Dec. 26 – is known as Boxing Day in the U.K. and the British Commonwealth.

Boxing Day is recognized as a public or bank holiday that provides time off for non-essential personnel, according to National Today, an online holiday calendar.

The day’s origin is reportedly unknown, but historians have found the term entered the Oxford English Dictionary in 1833 and was referenced in Charles Dickens' novel "The Pickwick Papers" in 1836.

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Boxing Day was likely an already established tradition before these 19th-century pop culture moments, according to History.com, a digital news source for the A+E Networks’ History Channel.

History.com reports that researchers are split between two theories about Boxing Day’s potential origins.

The first theory suggests Boxing Day may have come to be when British aristocrats distributed small gifts, money and Christmas dinner leftovers to household servants and employees after holiday festivities concluded.

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"These boxes were, in essence, holiday bonuses," History.com wrote in a "Why is the day after Christmas called Boxing Day?" report.

The second theory suggests Boxing Day may have evolved from the donation boxes churches put out to collect alms (money or food) to help people in need throughout the advent season, which typically runs from Nov. 30 to Dec. 24, according to National Geographic.

"Clergy members distributed the contents of the boxes to the poor on December 26, which is also the feast of St. Stephen, the first Christian martyr and a figure known for acts of charity," History.com reports.

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Today, Boxing Day is celebrated in the U.K. nations England, Scotland, Wales and Northern Ireland, and British Commonwealth countries, including Canada, Australia and New Zealand, according to National Today and History.com.

Common Boxing Day celebrations reportedly include shopping, visiting friends and family, giving back to charities and watching sporting events, including soccer, cricket, swimming and horseracing.

Fox hunting was once an annual Boxing Day tradition, but the sport was banned in Scotland in 2002 and in England and Wales two years later, according to New World Encyclopedia, a trademarked online information resource.

Countries that have bans on fox hunting reportedly simulate the sport by allowing participants to follow artificially laid trails to track foxes but not kill the furry animals.

Protestors have objected to legal and illegal fox hunting at sanctioned Boxing Day events throughout the U.K., according to multiple national news outlets, at the time of publication.