Royal expert Paul Dampier explained that the reason for this was purely down to superstition.
He told Fabulous Digital: “The Queen won’t let 13 people sit down at a dinner table, not because she is superstitious but in case guests are.”
Although undeterred by “unlucky” numbers, the monarch does harbour the odd supernatural belief.
Mr Dampier added: “She does believe in ghosts and has several lucky charms in her handbag.”
Royal banquets are governed by a whole series of strict etiquette rules that guests need to observe.
Royals are said to stay away from both because they can cause bad breath.
The Queen is expected to host President Joe Biden and leaders from the other G7 countries at the next official state banquet.