Meghan Markle made a surprise appearance at the Queen’s Christmas party

The newly-engaged Meghan Markle surprised guests with an appearance at the Queen’s Christmas party at Windsor Castle earlier this month,HELLO! has learned. The American actress, who wore a festive red dress, attended the party held for the Queen's hard-working staff with her fiancé Prince Harry. The couple mingled and chatted to workers, some of whom will be involved with their wedding in May. A source said: "Harry and Meghan spent about an hour at the party and they were really friendly and went around talking to everyone. Meghan was very sweet and so beautiful."

Harry, 33, and Meghan, 36, will say "I do" at St George's Chapel in Windsor. Meghan has been spending time at the royal residence, touring the rooms as she prepares for her wedding there. Next week, she and Harry will travel to Sandringham where they will celebrate Christmas with the royals. The former Suits actress is the first non-married partner to be invited to spend Christmas with the Queen and the rest of the royal family at Sandringham – a sign that she has been fully welcomed into the institution.

TAP TO VIEW THE GALLERYMeghan and Harry attended the Christmas staff party

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At her first joint engagement with Prince Harry in Nottingham, Meghan told one well-wisher: "I'm so happy, I've been made so welcome." The stunning brunette also revealed that she has had tea with the Queen on a number of occasions, and bonded with her future sister-in-law Kate, who is "wonderful". Meghan has also been getting to know Prince William and Kate's young children – Prince George, four, and Princess Charlotte, two – who live a stone's throw away from her and Harry's Kensington Palace home.

Christmas for the royals is steeped in tradition – something Meghan will experience for the first time this year. The Queen and Prince Philip usually retreat to their country home, Sandringham Estate, the week before Christmas, around 21 December, to prepare for the big family reunion. Other guests arrive at the 20,000-acre estate from 23 December in order of precedence, with Prince Charles and the Duchess of Cornwall usually the last to arrive.

The couple will marry at Windsor Castle in May

What will Meghan give the Queen for Christmas?

Presents are opened on Christmas Eve, followed by an afternoon tea and formal dinner, where the ladies don their finest gowns and jewellery and the men wear black tie. It is a relatively formal affair, but also the chance for the families to catch up. This year there will be plenty of exciting news to talk about; as well as Meghan and Harry's royal wedding in May, Prince William and Kate are also expecting their third child in April.

Meghan Markle and Prince Harry on their first royal engagement
A big Christmas tree and decorated Windsor State Apartment