The Duchess of Sussex once described motherhood as being on her "bucket list", while the Duke of Sussex has often confessed he would love to have children.
The former actress's pregnancy fulfils the pair's long-held ambition to become parents.
In the run-up to their wedding, Meghan hinted at starting her own brood with Harry.
On a trip to Belfast less than two months before the big day, the bride-to-be joked when she was shown an innovative range for newborns: "I'm sure at some point we'll need the whole (lot)."
In an interview in 2016, Meghan said becoming a mother was on her "bucket list".
"I can't wait to start a family, but in due time," she said.
The topic cropped up in the couple's engagement interview, with Harry speaking of their plans.
"You know, I think one step at a time, and hopefully we'll start a family in the near future," he said.
Harry has long since admitted he would love to have children.
Back in 2015 before he met and fell in love with Meghan, he revealed that seeing his brother's family continue to grow made him wish he had some of his own.
"Of course I would love to have kids right now but there's a process that one has to go through and tours like this are great fun," Harry said.
"Hopefully I'm doing all right by myself. It would be great to have someone else next to me to share the pressure, but you know, time will come and whatever happens, happens."
He is already godfather to five or six of his friends' children.
"I think the key to that is to be able to grow up, but also be able to stay in touch with your childhood side," Harry added of being good at the role.
Like Harry, who is known for being at ease with youngsters, Meghan has impressed onlookers with her affectionate nature when meeting children on royal walkabouts.
— PA Royal Reporters (@PARoyal) March 8, 2018
In Birmingham on International Women's Day in 2018, she hugged 10-year-old Sophie Richards, telling her she could achieve whatever she wanted to achieve, after learning the schoolgirl wanted to become an actress.
Meghan also spent time getting to know William and Kate's eldest children Prince George and Princess Charlotte in the run-up to her engagement, and was living nearby at Kensington Palace when the family celebrated the arrival of Prince Louis.
The celebrity, who shot to fame playing paralegal Rachel Zane in the American drama Suits, already has two "fairy god-daughters".
She described the children of her close friend Benita Litt as such in a 2016 post on her since deleted Instagram account, and the girls – Remi and Rylan – were among her bridesmaids at her wedding.
During their wedding ceremony, Harry looked tenderly at his bride and smiled when the Dean of Windsor spoke of marriage being the "foundation of family life in which children are born and nurtured".
The duchess's father Thomas Markle said he expected Meghan and Harry would want to try for children soon.
He told ITV's Good Morning Britain in an interview a month after the wedding: "She's wanted children for a long time and when she met Harry and she spoke about how much she loves him, there's got to be a child in the making, somewhere soon."