Being a member of Britain’s royal family comes with its perks, but being a member also includes following a long list of unofficial rules put forth by the monarchy. One of those rules is reported to be a specific bedtime routine maintained by Queen Elizabeth II that her guests are expected to follow while visiting with her.

Last July, Express uncovered a 2015 interview with Sir William Heseltine, one of the Queen's former secretaries, in which he told The Telegraph that if someone is to spend the night at one of the reigning monarch’s residences, they were not to turn in for the evening until the Queen had done so.

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"There'd be an hour or so in the sitting room of everyone sitting around making conversation, and nobody felt it right to go to bed before the Queen did," Sir William told the outlet at the time.

While the rule may be one the royals are intended to follow, the secretary noted that the protocol had previously been broken by Princess Diana. Sir Williams said the late princess, who was once married to the Queen's son Prince Charles, found the “long royal evenings” to be “agony.”

“... Diana was driven to such extremes that she’d excuse herself and go to bed,” he said. “Which was thought to be rather bad form, going to bed before the Queen.”

Queen Elizabeth II and Kate Middleton
Queen Elizabeth II and Kate Middleton arrive to visit Kings College, to open Bush House in central London on March 19, 2019. Getty Images/Niklas Halle’n