It will be the one of the most-watched pregnancies in modern times. So what will life be like for the newest member of the royal family? A royal family expert in Houston said certain traditions might change for the new generation of British royalty.
"She is going to be the most famous mother in the world. Whatever happens, she will be watched the whole time," said Cathy Hollowell, referring to the Duchess of Cambridge.
Hollowell is a former British journalist now living in Houston. She covered the royal family extensively and said it's tradition for a princess to become pregnant within a year of marriage. It took Will and Kate a little longer, but then again, the couple is known for bending the rules.
"These two live together, they met at university, they're very attractive people but they're also hard working people," Hollowell said.
Hollowell expects certain traditions will be followed.
"They will go through the regular royal procedure. They will have pictures taken on the lawn on a little rug of the baby or babies. Will she have a nanny? Of course she'll have a nanny. Who wouldn't have a nanny if they could."
And whether it's a boy or a girl, Hollowell predicts another tradition will hold.
"It won't be a modern name," she said.
But other customs might take a back seat. For example, Hollowell believes Kate's parents will play an active role in the child's upbringing.
"Her parents will be very involved. I think Carol, her mother, will be spending quite a lot of time with her," Hollowell said.
What about Uncle Harry and Aunt Pippa? Will the birth of a niece or nephew tame their wild side? Hollowell isn't so sure.
"Uncle Harry … that's going to be interesting, isn't it? Perhaps he'll mend his ways."
Some British expats living in Houston said they also think the Duke and Duchess of Cambridge won't be afraid to break the mold, much like Princess Diana did.
"I think he's strong enough to say what he wants for his own child and how he or she is raised," said Helen Taylor.
"It seems to me that William has benefitted from Kate Middleton's family and it all looks from the outside to be picture-book good," said Guy Streatfeild, who owns British Isles in Houston.
Hollowell said that while tradition might provide a foundation, the royal family has shown it can get with the times.
"The great thing about the royal family is that they follow the indication of the rest of society," she said.
Queen Elizabeth announced her first pregnancy just shy of her first anniversary. Princess Diana announced her first pregnancy 11 months after her marriage to Prince Charles. Diana was the first member of the royal family to give birth in a hospital.