Meghan gave a wave to the crowds, which included many Americans who came for a glimpse of Harry’s fiancee. Meghan wore a tan coat, a hat and caramel-colored suede boots clutching Harry's arm as the couple entered the church for the first time.
It is the first time a royal fiancee has been invited to Christmas celebrations. The Duchess of Cambridge did not attend Christmas services at Sandringham in 2010 when she was still engaged to Prince William. She spent Christmas with her family before her wedding to William the next year.
Other royal fiancees have traditionally not attended either. Mike Tindall, the husband of Queen Elizabeth's granddaughter Zara Philips also did not join the royal family for Christmas before the couple married.
Later today, Queen Elizabeth will honor people affected by the 2017 terror attacks in the U.K. and speak about the theme of “Home” in her annual Christmas message.
Looking back on the past year, Queen Elizabeth will say, “We think of our homes as places of warmth, familiarity and love... there is a timeless simplicity to the pull of home."
She will also pay tribute to the 2017 U.K. terror attack victims and all the first responders who helped in the aftermath. "This Christmas, I think of London and Manchester, whose powerful identities shone through over the past 12 months in the face of appalling attacks," she is expected to say.
Queen Elizabeth will also pay tribute to The Duke of Edinburgh, who retired from official public duties during 2017. She will voice praise for his "support and unique sense of humor."
Markle, 36, and Harry, 33, announced their engagement Nov. 27 and, just a few days later, attended their first official engagement as a newly engaged couple in Nottingham, England. They plan to wed at Windsor Castle in May.
Markle called Queen Elizabeth "an incredible woman" in her first joint interview with Harry after their engagement announcement last month.
"It's incredible, I think, to be able to meet her through his lens, not just with the honor and respect he has for her as the monarch but the love that he has for her as his grandmother," Markle said. "All of those layers have been so important for me so that when I met her, I had such a deep understanding and, of course, incredible respect, for being able to have that time with her.”
Added Harry with a smile, "And the corgis took to her straight away," referring to Queen Elizabeth's beloved dogs.
Gifts are traditionally opened by the royal family Christmas Eve. Expensive gifts are frowned upon. Rather, members of the family will often swap funny gifts. Kate reportedly made homemade jam one year as gifts for her royal relatives.
After lunch, the entire family sits down to watch Queen Elizabeth’s annual televised Christmas message.
In the evening, the royal family gathers again for a Christmas buffet dinner with 15 to 20 different delicacies prepared by Queen Elizabeth’s chef. A toast is part of the meal, which ranges from roast beef to turkey and ham.
After Christmas, Markle and Harry are expected to take a holiday. Kensington Palace has confirmed Markle will take some time off before the wedding to see her friends and family in the United States.
Meghan and Prince Harry are starting to slowly make plans for their May 2018 wedding at St. George’s Chapel at Windsor Castle, with planning expected to really pick up in the new year.
Kensington Palace also announced that Markle will join the Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry once she weds Harry. She will give up her charitable work with World Vision and as a United Nations advocate for women to focus on the U.K. charities that William, Kate and Harry support.