It has previously been thought that Prince William and Kate had made a decision to delay the announcement because they didn't want to overshadow such an important day as Anzac Day.
She was eventually called Margaret Rose, but her parents, the Duke and Duchess of York, later George VI and Queen Elizabeth, were planning to call her Ann Margaret, but changed their mind after learning that King George V disliked the name Ann.
The folks at the Mail spotted that the website had one rather curious page that had restricted access to the public and we're all taking it as a clue about the royal baby's name. "Can't complain about that".
"Sleeping's going reasonably well so far", he said. "Arthur has resumed its position as the favourite, but it wouldn't be a huge surprise to see the odds flip flop once more".
Harry Aitkenhead, of Coral, said: "Arthur remains at the head of the market but has now been joined by Alexander after a flurry of bets yesterday".
Pippa and her hedge fund manager husband walked down the aisle in August 2017, and a source revealed the couple started three months after exchanging vows "trying for a baby".
Despite being understandably exhausted, Prince William told reporters that the baby is doing "very well, thanks".
It's expected once he has met his new grandson, the name will then be revealed.
Australian High Commissioner Alexander Downer also suggested Alexander to the Duke, to which he replied cryptically: 'Funny you should say that.It's a good name, ' The Sun reports. "It's a good name".