Markle and Harry will wed on May 19, and after the nuptials, Markle will then be known as Her Royal Highness Princess Henry of Wales, following the rules governing the British crown.
The British monarchy states that the title of "Princess" only applies to those born into the family, like Princess Charlotte, although Kate Middleton is technically styled as Princess William and is considered a princess by marriage, according to the blog Royal Central.
While Harry's mother, Diana, was styled as Diana, Princess of Wales, the title alone did not make her a princess, despite the public's common reference to her as Princess Diana, a courtesy title held by the wife of the Prince of Wales.
It has been speculated that Harry will be made a duke and Markle a duchess after their marriage, which would also give the former Suits star a new title. Before dukedom can be granted, it must be available, and the pair is expected to be awarded Sussex, according to Royal Historian Marlene Koenig.
The title was last held by Prince Augustus Frederick, who died in 1843. Should that be the case, Harry would become the Duke of Sussex and Markle would become Her Royal Highness Meghan, Duchess of Sussex.
When Prince William married Middleton, he added the Duke of Cambridge to his title and Middleton became Her Royal Highness, Catherine Duchess of Cambridge after the Queen granted the dukedom to the pair.
Should Harry and Markle have children, the new royals could be deemed princes and princesses should the Queen allow it, like she did for Princess Charlotte. Page Six shares that according to royal rules, only HRH Prince George would have been a prince while Charlotte would have been Lady Charlotte Mountbatten-Windsor had the Queen not issued a new patent ahead of Charlotte's birth.
The patent stated that “all the children of the eldest son of the Prince of Wales should have and enjoy the style, title and attribute of royal highness with the titular dignity of Prince or Princess prefixed to their Christian names or with such other titles of honor.”
Another decree may be made for Harry and Markle's children, as they will be born into the royal family.
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