His parents Prince Harry and Meghan Markle may have the royal titles of the Duke and Duchess of Sussex.
But for their son Archie - he's plain Archie Harrison Mountbatten Windsor, as he has no royal title.
However, this could all change in the future and he could become a prince with a HRH style and it's down to a rule set down more than 100 years ago. But will only happen when his grandfather Prince Charles becomes King.
The tradition stems from Harry's great-great-grandfather, George V when he issued a Letters Patent in 1917.
A spokesperson for Debrett’s previously told the Mirror: “In 1917, King George V ordered that only the grandchildren of the monarch would be entitled to use the style of prince or princess and HRH, the only exception to this order was that the eldest son of the eldest son of the Prince of Wales would also be entitled to use the style HRH and Prince."
This means that only Prince George - as a great-grandson of the monarch down the direct line of succession to the throne - was originally entitled to be a prince. He is the eldest son of the eldest son of the Prince of Wales.
The Queen stepped in ahead of George's birth to issue a Letters Patent to ensure all the Cambridges' children would have fitting titles.
However, this does not extend to Archie and his younger sister Lilibet - although when Charles is King they will be the grandchildren of the monarch and can be styled HRH and prince or princess.
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It was originally believed that Harry and Meghan were involved in the discussions about how Archie's would be styled, with suggestions they didn't want him to have a title to allow him to have a more 'normal' life.
But in their bombshell interview with Oprah Winfrey, Meghan said this wasn't the case and said they wanted him to have a title for protection reasons.
She suggested the decision may have been to do with race, saying there had been "conversations" about the colour of his skin.
However, Debretts explained that Meghan and Harry did have the option to give their son a title if they wanted to.
It said: "In accordance with the 1917 order, Archie could now use his father's title of the Earl of Dumbarton and could be referred to as Lord Dumbarton."
However, it was reported last year that Harry and Meghan weren't keen to give Archie this name.
A Telegraph source said: “They didn’t like the idea of Archie being called the Earl of Dumbarton because it began with the word ‘dumb’. They were worried about how that might look.”
Another insider claimed: “It wasn’t just Meghan who pointed out the potential pitfalls, it also bothered Harry.”
