Royal Baby Kate Middleton
Photo: Getty

Prince William and Kate Middleton just welcomed their third child this morning, and while they’ve kept royal fans in the dark about his name, there are already clues to what the new prince’s official title will be.

Royal expert Marlene Koenig told Town & Country that since the child is a boy, his official title would technically be His Royal Highness Prince [name] of the United Kingdom of Great Britain and Northern Ireland.

However, if the baby is a child of a royal duke (like Prince William, the Duke of Cambridge), the names are “styled differently” than what’s listed above, Koenig added. Just take a look at the current royal kids’ birth certificates. Prince George‘s name and surname are listed as: His Royal Highness Prince George Alexander Louis of Cambridge.

Related article: Duke And Duchess Of Cambridge Welcomes Royal Baby Number 3

And Charlotte’s are written as: Her Royal Highness Princess Charlotte Elizabeth Diana of Cambridge.

Related article: Prince William and Kate Middleton’s Third Child Will Not Have a Last Name

If the Duke and Duchess of Cambridge follow tradition (as they usually do), their third child will go by the same title as its siblings: His Royal Highness Prince [name] of Cambridge.

Koenig added that royal baby number three will technically be a commoner, since, in the U.K., “the only people who are not commoners are the Sovereign and peers of the realm, [people with titles like] Duke, Marquess, Earl, Viscount, and Baron.” In fact, according to a Letters Patent King George V passed in 1917, only the oldest living son of the eldest son of the Prince of Wales is allowed to “have and enjoy in all occasions the style and title enjoyed by the children of Dukes of these Our Realms.”

That meant George was always entitled to be HRH Prince George of Cambridge, but Princess Charlotte would’ve been named Lady Charlotte Mountbatten-Windsor, the Independent reports. However, in 2012, the Queen issued a Letters Patent before she was born to ensure Charlotte would also be a “royal highness.”

The decree 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 honour.”

Therefore, Charlotte and all her younger siblings (however many she may have), can share the same title as big brother Prince George.

Prince Harry and Meghan Markle‘s children, on the other hand, will not have the title of “Prince” and “Princess,” according to the Letters Patent of 1917 and the Queen’s patent in 2012. Instead, they’ll be titled Lord/Lady [name] Mountbatten-Windsor—unless the sovereign steps in to make any changes.

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This article originally appeared on Harper’s BAZAAR US