Prince Louis is the youngest of the Wales clan who won over a legion of new fans during the late Queen's Platinum Jubilee celebrations.
He kept everyone entertained with his cheeky antics and the hilarious faces he pulled on the Buckingham Palace balcony.
The four-year-old is now fourth in line to the throne behind his dad Prince William and older brother and sister Prince George and Princess Charlotte.
His official title is His Royal Highness Prince Louis of Wales - but it turns out he only became a prince when he was born thanks to his great-grandmother the late monarch.
This is because she intervened to overwrite a rule put in place by King George V.
Back in 1917, he set out new guidance on which royals were allowed to have titles - and who was too far down the line of succession to qualify for one.
He decided that all of the sovereign's children would automatically become a Prince or Princess, as well as any grandchildren born through the male line. However, great-grandchildren weren't included on the list.
This caused a bit of an issue when George was born, as despite being our future king he shouldn't have had the title.
The then Queen stepped in and said that George would get a title, and decided to extend the change to all of Kate and William's children.
Of course, if she didn't make the change, he still would have eventually become a prince when his grandfather King Charles took the throne back in September.
In recent weeks there has been speculation about whether Charles’ other two grandchildren, Archie and Lilibet Mountbatten-Windsor, will be granted princely titles.
Some experts have even suggested that the delay to any official announcement on the subject has been caused by the upcoming release of Prince Harry ’s memoir ‘Spare’ which has previously vowed to offer “raw, unflinching honesty”.
Vanity Fair's royal correspondent and author of The New Royals: Queen Elizabeth’s Legacy and the Future of the Crown Katie Nicholl believes Charles will keep his cards close to his chest until the publication date.
She writes: "Now that Charles is king, Harry and Meghan’s children automatically become Prince Archie of Sussex and Princess Lilibet of Sussex; however, the royal family’s website still has them listed as Master Archie Harrison Mountbatten-Windsor and Miss Lilibet Mountbatten-Windsor.
"Would Charles go as far as barring Archie and Lilibet from becoming a prince and a princess now that the Sussexes are no longer working royals?
"According to a source close to the king, it depends a lot on what happens in the coming months, particularly with Harry’s book and their TV show."
