One of Philip’s cousins, Lady Pamela Hicks made the revelation while talking to historian Sally Bedell Smith for her biography of the monarch in 2012.
“In England, the upper class always have had separate bedrooms,” Sally admitted.
“You don’t want to be bothered with snoring or someone flinging a leg around.”
“Then when you are feeling cosy you share your room sometimes. It is lovely to be able to choose,” she said.
In addition to sleeping in separate beds, Her Majesty and Prince Philip are rarely seen holding hands – or showing any kind of affection in public.
Royal etiquette expert Myka Meier previously told People there are no formal rules on royal couples being lovey-dovey in public.
“Senior members of the royal family would likely not be told how to interact or when they can or can not show PDA and would be trusted to use their better judgement as to when it’s appropriate,” Myka said.
“The royals often adjust PDA to mirror the formality of the event they are attending.
“At a sombre or more formal event, we are less likely to see PDA than at a casual event where it would be deemed more fitting,” she added.