Entertaining members of the Royal Family must be pretty nerve-wracking , particularly as a plethora of rules are usually enforced. According to a royal author , one former American president was "horrified" during a visit from King Charles for a slightly embarrassing reason.

Speaking to Hello! magazine , David Charter—author of Royal Audience: 70 Years, 13 Presidents—One Queen's Special Relationship With America —explained, "Ronald Reagan was horrified when he had Prince Charles into the Oval Office and they brought him a cup of tea that still had the tea bag in it, and he could see that he wasn't drinking this cup of tea, and he thought he'd made a terrible faux pas."

Luckily, according to Charter, the "tea bag" debacle would be considered "a very small little faux pas" to members of the Royal Family.…