In an interview with Australian Women's Weekly the royal couple revealed that they don't know if their little one is a boy or a girl and will be eagerly awaiting to find out when he or she arrives in January 2014.
"I'm really looking forward to it," said Mike. "But I'm not sure how I've prepared. We've been pretty relaxed. We've not sorted a nursery yet.
"It probably happened quicker than we thought," he laughed. "[It was a] Bit of a shock, really."
Having not planned on getting pregnant as quickly as she did Olympic equestrian star Zara had to swiftly make changes to her riding schedule.
Following the news of her first pregnancy 32-year-old Zara initially continued riding but has now had to stop.
"I have been riding, but it's so uncomfortable," she said. "So, yes, I'm baking. I love cooking and will definitely cook for the baby.
"I hope we're going to make good parents," added Zara. "That's the plan."
Princess Anne's daughter will certainly be able to practice her parenting skills on William and Kate's baby Prince George, having recently been announced as his godmother.
On the day of his christening Zara was announced as one of George's seven godparents, who also include Julia Samuel, William van Cutsem, Oliver Baker, Emilia Jardine-Paterson, Earl Grosvenor and Jamie Lowther-Pinkerton.