Meghan Markle
Meghan Markle will have a royal title, but it won't be Princess Meghan. Here, she arrives at the Cliveden House Hotel in Berkshire, England, to spend the night before her wedding on May 18, 2018. Steve Parsons-Pool/Getty Images

Though she is marrying a prince today, Meghan Markle won't be able to refer to herself as Princess Meghan.

While Markle is the wife of Prince Harry, her royal title won't ever include the "Princess" moniker, due to royal protocol. Like Kate Middleton, currently the Duchess of Cambridge, because Markle is not from a royal bloodline, she is unable to refer to herself as "Princess Meghan." However, because their husbands are princes, both women are able to adopt their names when it comes to the Prince and Princess titles. The Duchess is also given the title Her Royal Highness, Princess William of Wales, and Markle will likely have a title of Her Royal Highness, Princess Henry of Wales.

In addition, Harry's place in the line of succession also plays a role in the titles that they will inherit. Because he is now sixth in line for the throne and is considered much less likely to ever be crowned King, he and his wife are not likely to earn extra titles.

However, any children they have will be referred to as Prince and Princess because they will have a part of the royal bloodline in them because of their father. The same rule applies to Prince William's three children as well—their official titles are Prince George of Cambridge, Princess Charlotte of Cambridge and Prince Louis of Cambridge.

Still, while Markle may not ever be Princess Meghan, she is expected to receive a title following her wedding. Following their 2011 nuptials, William and Kate were granted the Dukedom of Cambridge, giving them their current titles as the Duke and Duchess of Cambridge. It seems unlikely that a similar grant wouldn't be extended to the newlyweds.

As for which province they will be the Duke and Duchess of, the most believed duchy is that of Sussex, which is available for them, though there are also similar titles available for Clarence, Avondale, Connaught and Windsor, the same area where they are marrying. Whichever one they are granted, their titles are expected to be Henry and Meghan, the Duke and Duchess of that area.