Doria Ragland, 62, reportedly impressed senior royals with her demeanour at the wedding of her daughter and Prince Harry. A source says the invite serves as "a mark of respect" from Queen Elizabeth II.
Typically, non-royals do not spend the night at the Norfolk estate, and while Middleton's family has attended church with the royals on Christmas morning, they have not spent the night.
As The Cut notes, Markle and the Queen appear to have a special bond with their shared love of dogs, among other things. Instead, they have stayed at nearby Amner Hall rather than Sandringham, where the Queen resides during her trips to the country.More news: England star George Burgess charged over gouging allegation
She has remained respectful of the royal family and her daughter, unlike Meghan's father, Thomas Markle.
We're looking forward to seeing what type of fabulous fascinator Ms. Ragland will rock for the festivities.
"Doria's quiet dignity and grace at the Royal wedding has earned her enormous respect from Meghan's new in-laws", the source tells ET.More news: Single mother of 3 claims half of $700M Powerball jackpot
He later said he had apologised to both Harry and Meghan and denied staging the shots for money, insisting they were taken in a bid to "change his image".
The source added: "Queen Elizabeth is very aware of all the problems Meghan has had with her dad and sister and she feels sorry for her that she doesn't have family and a support network close by". Meghan is very close to her mum.
The invitation to Christmas dinner has also fuelled rumours that Doria Ragland may move to London, from her home in Los Angeles.More news: Arsene Wenger emphatically denies he is taking over at AC Milan
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