The Suits actress will solidify her role in the royal family by joining her future in-laws for the traditional Christmas festival gathering.
A Kensington Palace spokesperson said: 'You can expect to see The Duke and Duchess of Cambridge, Prince Harry and Ms Markle at Sandringham on Christmas Day.'
Royal watchers believe that royal protocol is being broken if Markle attends, as usually spouses have only attended the ceremony after the couple have married.
Richard Fitzwilliams, a royal expert, told Express, 'In 2010 Kate was not invited after her engagement to William nor was Mike Tindall after his engagement to Zara Phillips. Only spouses and close family are usually invited.'
'However, Harry and Meghan will be living together in Nottingham Cottage at Kensington Palace and her family are in the United States,' he continued. 'The monarchy relies heavily on precedent and tradition but it also makes its own.'
The Queen hosts a traditional gathering every year at her Norfolk retreat, which is believed to include presents and games on Christmas Eve.
On Christmas morning, the royal family all attend a service at St Mary Magdalene Church on the estate.
The Queen often drives while other members of the family walk the short distance from the house to the church where a crowd of well wishers wait to greet them outside.