Meghan Markle and Prince Harry attend Queen Elizabeth II's annual Christmas lunch

Prince Harry and Meghan Markle arrive together at the annual Christmas lunch for the extended Royal Family at Buckingham Palace on December 20, 2017 in London, England. (Getty)

Meghan Markle and Prince Harry have reunited in London, and this time the couple’s public outing involved the queen.

On Wednesday, Prince Harry and Markle were snapped driving into Buckingham Palace for Queen Elizabeth’s annual pre-Christmas party, a traditional event for the royal family.

Joined at the event by Harry’s immediate family ─ Prince William, Duchess Kate, Prince George and Princess Charlotte ─ this was the first time the American actress had the pleasure of dining with the entirety of the royal family.

Prince Harry and Meghan Markle spent the afternoon with Harry's extended family members for the Christmas lunch at Buckingham Palace. (Getty)

More than 50 family members including Prince Charles, Camilla, Duchess of Cornwall, Princess Eugenie (who was one of the first to arrive), Princess Beatrice and Zara, as well as Mike Tindall, were present for the traditional celebration.

William and Kate drove into Buckingham Palace with their children and the royal nanny, Maria Turin Borrallo, in the back seat, while Harry drove his fiancée to the event from their home at Kensington Palace in a Land Rover.

According to People, inside the palace, Meghan rubbed elbows with several members of the royal family, including the queen’s children. And although she had already met the queen on a few smaller occasions, this was said to be the first time Meghan was with the whole family for an event all at once.

This is the first event where Markle spent time with the entire royal family. The actress will join Harry's immediate family at the Queen's estate in Sandringham on Christmas Day. (AP)

Meghan is slowly starting to meet extended members of the royal family and has also been introduced to members of the royal household. People reported the queen recently took Meghan and her grandson to a private party for royal staffers at Windsor Castle.

In her BBC engagement interview with Harry, Meghan described meeting the queen as “incredible."

After Christmas, the couple will take a pre-wedding vacation before moving forward with more wedding planning. (AP)

“To be able to meet her through [Harry’s] lens, not just with his honor and respect for her as Monarch, but with the love he has for her as his grandmother. She’s an incredible woman,” she said.

Harry even joked that not only did the queen approve of his fiancée, so did the queen’s beloved corgis.

“The corgis took to [her] straight away . . . I spent the last 33 years being barked at; this one walks in, absolutely nothing!"

Following the queen’s annual Christmas lunch, Meghan is set to join the royal family at the queen’s estate in Sandringham on  Christmas Day, an exclusive event that is only open to family and spouses.

Meghan broke tradition by being the first fiancée invited to attend the queen’s special Christmas Day event.