Could Kate give birth to twins this time?
The palace have released very little information on the baby's gender, there have been some rumours the royals are expecting twins - with Prince William even commenting on the matter!
We explore what would happen in the Duchess has twins, and how the royal succession would work.
Could Kate Middleton be having twins?
There's no official line about the sex of the Duke and Duchess of Cambridge's third child, but bookies are betting it'll be a girl.
However, there was a recent report form a US publication that said Kate Middleton is expecting identical twin girls.
The front-page feature used a source which claimed the news of twins had been leaked from Kensington Palace itself.
The reports are unfounded, and Kensington Palace hasn't commented.
How would the royal succession work?
Gender is no longer an overriding factor in royal successions, with the rules being changed in 2011 allowing sons and daughters of royal monarchs having equal right to the throne.
This means Prince Charlotte would still remain the fourth in line for the throne if the new baby was a boy.
Her older brother Prince George is currently third in line.
This means that if Kate had twins, regardless if they were both male, both female or one male and one female, it would be the baby delivered first who succeeds.
What has Prince William said about it?
Though Prince William did not comment on the US article directly, he has discussed the idea of twins.
While attending the Centrepoint Awards at Kensington Palace, he dismissed the speculation.
"Twins? I think my mental health would be tested with twins," he said.
“Two is fine, I don’t know how I’m going to cope with three, I’m going to be permanently tired.”
Bookies predict names for the royal baby - is your favourite in there?
William Hill's most likely girls names are Alice (4/1), Mary (11/2), Elizabeth (6/1) and Victoria (6/1) .
If the Duke and Duchess have another boy, William Hill estimate that Arthur (5/1), Albert (9/1) and Jack (9/1), will be popular choices.