The expectation is that Prince George of Cambridge will one day become King George VII when he succeeds his father to the throne, but as with all things royal, the truth might not be quite so simple.
Upon accession to the throne, monarchs are perfectly entitled to be crowned by any name of their choosing, and will thereafter be known by that name.
The Queen’s father, King George VI, was the last monarch to assume a different regnal name, having been born as Prince Albert. King Edward VII also shunned the name Albert when he came to the throne.
It has been widely speculated that Prince Charles may decide to rule under a different name, perhaps King George, considering it is one of his middle names. The Prince of Wales is alleged to believe that the name Charles is unlucky, with the previous monarchs ruling under that name having the most unfortunate of reigns.
The Prince of Wales’s full name is Charles Philip Arthur George, and so could choose to use any of these as his regnal name. The same goes for William Arthur Philip Louis and also for the young George Alexander Louis.
Whether or not the Prince of Wales will decide to rule as King Charles III, King George VII or even perhaps something completely different remains unknown. We will only learn of his regnal name once he assumes the throne.