The Duke and Duchess of Cambridge are expected to pick a traditional royal name for their newborn baby Prince.
Royal infants mostly have historical names which are passed down through the generations.
Charles Kidd, editor of Debrett's Peerage and Baronetage, predicted that William and Kate would select a conventional first name for their son.
"I do think that Prince William is quite a traditionalist – that's my feeling," Mr Kidd said.
"The fact that he chose to use the royal dukedom (of Cambridge) and has followed royal precedent, I wouldn't be surprised if they use a name that is already familiar in the royal family – something that has royal associations."
He suggested that George – a favourite at the bookmakers – could be their name of choice. There are also predictions that the couple will honour William's father the Prince of Wales by choosing Charles and the Duke of Edinburgh by selecting Philip.
Midway through her pregnancy, Kate revealed she and William had a shortlist of names and that her friends were giving her ideas.
"We have a shortlist for both (boy and girl) but it's very difficult. My friends keep texting me names," she told a well-wisher.
The baby, who will eventually be King, will be styled HRH Prince (forename) of Cambridge. One day the baby is also likely to become the Prince of Wales. The title is usually given to the male heir to the throne, but it is not automatic.
Here's a look at some potential names for the Cambridges' baby son:
1. George: A popular royal name, with six King Georges having worn the crown throughout history since the German-born George I, the first Hanoverian king of Great Britain, acceded to the throne in 1714. As a name, it has come to symbolise the continuity of the monarchy.
The first name of the last King George – George VI – was actually Albert and he was known to his family as Bertie, but he selected George – his fourth name – for his name as Sovereign. It is also the Prince of Wales's fourth name.
2. Charles: William is likely to want to honour his father in the naming of his son. Charles is also the name of Diana, Princess of Wales's brother, Earl Spencer.
3. Philip: William and Kate are also expected to acknowledge William's grandfather and the Queen's consort the Duke of Edinburgh in the names they pick. Both Charles and William have Philip as a middle name.
4. Francis: Francis is a recurring name in Kate's family tree. It is the middle name of both her father and her grandfather. The feminine form of Francis, Frances, was also Diana, Princess of Wales's middle name.