Queen Elizabeth II has a strict bedtime rule on Christmas day.

The royals will be spending their Christmas at the monarch's Sandringham House residence in Norfolk. According to Carly Read, a journalist for Express, everyone must stay up until midnight and play charades until the Queen announces that she has had enough of the game. Otherwise, they might upset Her Majesty.

In addition, Queen Elizabeth has three strict rules when it comes to exchanging gifts and when they can open it. The members of the Firm usually do this on Christmas Eve in the red drawing room at Sandringham. According to Tom Davidson, an online reporter for Mirror, the rules are as follows:

First, no one should open their present until given permission by Prince Philip, who supervises the proceedings. Second, every present should be a cheap "joke gift." And third, the cheaper the gift, the better.

The royals open their Christmas presents a day earlier than when most usually do because of their German heritage. "The royals are of German descent so they weave in German traditions to their celebrations," former royal chef Darren McGrady explained. "After afternoon tea, they open gifts on Christmas Eve, as is the German tradition."

For the upcoming event, Queen Elizabeth II invited Markle's mom, Doria Ragland, to spend the holidays with them. In fact, Ragland will join them in their special Christmas dinner, which Kate Middleton's parents have yet to attend. According to a source, the Queen is doing this for the pregnant royal.

"It's a mark of the Queen's respect for Meghan and an acknowledgment that she doesn't have any other relations in this country - unlike Kate who has the support of a very close family," a source said

As for Ragland's Christmas break in London, she should expect busy days ahead. There will be lots of funny presents, afternoon teas and delightful meals.

"After her luggage is unloaded, there will be a present-giving ceremony after tea," Ingrid Seward told Grazia magazine. "There are mainly useful things, such as homemade jams, china or curios bought from county fairs."

Queen Elizabeth II
Queen Elizabeth II has a Christmas bedtime rule that all the members of the royal family must follow. Pictured: Queen Elizabeth II is seen at the Chichester Theatre while visiting West Sussex on Nov. 30, 2017 in Chichester, United Kingdom. Getty Images/Stuart C. Wilson