But the Duchess of Cambridge isn't the only famous lady to be pregnant in 2015.
Actors Keira Knightley and Joanna Page will also be dressing in maternity wear this year, as will TV presenter Charlotte Hawkins. Not to mention Benedict Cumberbatch and his fiancée Sophie Hunter, who caused a social media meltdown when they announced that they have a #Cumberbaby on the way.
It is also set to be a bumper year of babies for soap stars, with Coronation Street's Catherine Tyldesley starting the year pregnant, as well as former Corrie actress Helen Flanagan, EastEnder Jacqueline Jossa, former EastEnder Martine McCutcheon, Holby City's Rosie Marcel, and former Emmerdale actress Adele Silva.
As well as actors and presenters, the baby bug has also spread to stars of the pop and sporting worlds.
Olympic swimmer Rebecca Adlington's first child will be born in 2015, as will footballer Peter Crouch and Abbey Clancy's second child, and Man City defender Pablo Zabaleta's first child with his wife Christel Castano.
And it's not just UK celebrities who will be welcoming new babies this year. Americans Liv Tyler, Milla Jovovich, Ashlee Simpson, Jennifer Love Hewitt and Alec Baldwin all have babies on the way.
Check out the gallery below for the full list of famous mums- and dads-to-be who are currently expecting.
You can also meet the celebrity mums and dads who welcomed babies last year with our round-up of famous babies born in 2014.