Princess Diana hated spending Christmas with the royal family and was very keen to find time alone, according to royal experts.
The festive season could become "too much" for those not used to royal traditions, such as the former Princess of Wales.
"Diana did not like Christmas with the Windsors," royal commentator Lady Colin Campbell told the Express.
"She was very keen to disappear into her room as much as she could."
Princess Diana also broke a longstanding tradition during her first Christmas with the royal family, it is claimed.
The King and his family have many festive traditions including the giving of joke gifts.
One year, Kate Middleton gave Prince Harry a 'grow your own girlfriend kit' before his romance with Meghan Markle began.
Prince Harry reportedly made the late Queen chuckle with his gift to her - a shower cap that read "ain't life a b***h".
Meghan also impressed Queen Elizabeth during her first Christmas with the royals as she gave her a singing hamster on a string - which the royal corgis thoroughly enjoyed.
But as a newlywed in 1981, Diana was not aware of the tradition and decided to play it safe by gifting a cashmere jumper to Princess Anne, experts told the Royals podcast.
"When Diana first went she didn't know that there was this joke present tradition," writer Zoe Borrell said.
"So she had got Princess Anne this gorgeous cashmere jumper.
"It was all very sensible and expensive. And she handed it over and she hadn't been made aware that it was just novelty presents.
"Poor thing. They don't communicate very well."
Zoe said that Charles "should have told her" about the joke presents before they all swapped gifts.
While royal writer Angela Mollard explained: "I don't think they were talking much.
"They got married in August and I don't think they were talking by December.
"So he didn't give her that information and she was very annoyed about it."
The following year, Diana had been told about the Secret Santa premise and gave Fergie a leopard-print bath mat.
But it was said she did not enjoy spending Christmas with the other royals at the countryside retreat.
Royal chef Darren McGrady claimed Diana was more interested in talking to staff than the other dinner guests.
"Once the Queen and the royals had left the dining room, Princess Diana just liked to come in for a chat," he told Yahoo.
The chef said she "just sort of walk around the kitchen" to see what was going on.
“Sandringham was so tight, so compact, there were so many people there, all the families," he added.
"You just couldn’t get away. You came out of the dining room and you couldn’t go into the sitting room because there were three or four people in there playing charades or Scrabble or something."
Mr McGrady said he would bump into the former Princess of Wales who would go off for a walk on her own.
While her former butler Paul Burrell told how she would confide in him that she would be "crawling the walls" by the end of a Christmas at Sandringham and "couldn’t wait to escape".
This year was the first the royal family spent without Queen Elizabeth who died in September.
Her late Majesty celebrated 32 Christmases at the royal estate and this year, it was continued by King Charles and Camilla Queen Consort.
The Prince and Princess of Wales were among senior royals to join them at the Norfolk estate with their children Prince George, Princess Charlotte and Prince Louis.
As part of another royal family tradition, the youngsters reportedly unwrap their presents at teatime on Christmas Eve.
Then on Christmas Day, children eat separately to adults for their festive meal, according to Mike Tindall.
The former rugby player, who is married to the King's niece Zara Tindall, explained that the youngsters traditionally sit in a separate room for the event.
