A few months ago she gave a big hint by mistake when she thanked someone for a toy present and said: "Oh, I'll give it to my dau........" and everyone thought she was going to say "daughter".
Royal babies are always big business - you can buy cups and plates, and T-shirts and special coins which are on sale for the event.
This time...and this is kind of strange - the baby's grandparents will actually be making big money out of this birth.
Carole and Michael Middleton own Party Pieces a very successful mail order site for children's party accessories, the About Us page has a picture of Catherine's mother with pirate accessories!
This business is going to do VERY well out of the birth of this royal baby. There is nothing (at the moment) which is directly about Catherine's baby, but I'm sure anyone planning a kids' party this summer would love to buy from this company and say "Oh, these paper cups come from Kate's parents' company!!!"
And of course, at the moment journalists are checking the site to see if there are any hints about Boy/Girl.
The baby's other grandparent...Prince Charles, is also cashing in on royal baby fever.
His country house is called Highgrove and on the website for that house and garden is here Highgrove
Money from sales on this website go to Prince Charles' charities.
What can we find on this website for babies??? Cute little baby shoes with the British flag on them!!