Meghan Markle and Kate Middleton both have to follow this strict footwear rule

From pantyhose to conservative hemlines, there seems to be an endless list of royal dress codes that Meghan Markle has had to adopt since becoming the Duchess of Sussex on May 19th. And though her style transformation from commoner to duchess is worthy of a princess, and has indeed proven her commitment to her new royal identity, we had no idea just *how* extreme the evolution would be.

One royal rule she's recently had to adopt? Closed-toe shoes. And closed-toe shoes only.

Of course, the dress code doesn't just apply to Meghan, but it's a rule that the Duchess of Cambridge, the Duchess of Cornwall and even Princess Eugenie seem to adhere to.

Photo: Getty

Said etiquette expert William Hanson to Harper's Bazaar: "Open-toed shoes are considered informal footwear and inappropriate for formal occasions." Hanson explained that it was even "requested" that guests attending the May 19th nuptials ditch their open-toed shoes in favor of more formal footwear, though some of the higher-profile guests made their own rules.

RELATED: Strict royal rules:

And though it'll be very rare to see a royal sporting wedges, you'll never, ever see Meghan or Kate sporting the footwear around their grandmother-in-law Queen Elizabeth. Explained a source to Vanity Fair, "She really doesn’t like them and it’s well known among the women in the family.”

It's Liz's world, and we're just living in it.