"The royals are of German descent so they weave in German traditions to their celebrations," former royal chef Darren McGrady told the Express.
"After afternoon tea, they open gifts on Christmas Eve, as is the German tradition."
The royal family's website confirms: "On Christmas Eve, The Royal Family lay out their presents on trestle tables and will exchange their gifts at teatime."
This tradition is one the Duchess of Sussex, and her mother Doria, may have to get used to. It's been reported that Doria has been formally invited by the Queen to attend the Royal Family's festive celebrations.
On Christmas Day, it's an early start for the royals with not one but two church services in just three hours.
The first service, at 9am, is a private one for the family - so the Queen can take communion.
They then return home for a change of clothes before the public service at St Mary Magdalene Church at 11am.