The couple's daughter is due in the summertime – a short time after her big brother Archie celebrates his second birthday on 6 May. But unlike Archie, the baby will be born in the States.
Meghan, 39, gave birth to Archie at the Portland Hospital in 2019, when Harry and Meghan were living together at Frogmore Cottage in Windsor. His little sister, meanwhile, will be born in California, where the couple now reside with their son.
WATCH: Prince Harry and Meghan Markle reveal baby's gender
But what is Archie's nationality? And will his sister hold the same status?
Since Archie was born in the UK he automatically became a British citizen, and given that his mother is American he is also eligible to become a US citizen.
Archie Harrison is set to become a big brother in the summer
For Meghan to be able to pass down her citizenship to her son, she had to have lived in the US for 10 years prior to his birth, which, of course, she did. Archie, therefore, is a dual British and American citizen.
The couple's daughter will benefit from the same law and will be both a US and British dual citizen, like her brother.
The couple's son was born at the Portland Hospital in London
It is not known exactly when Harry and Meghan's baby is due, with the Duchess simply stating she was expecting her baby in the summer in her divisive interview with Oprah Winfrey.
No doubt her mother, Doria Ragland, will be among the first to meet the new arrival. The royal couple live in California's Montecito, which is approximately a one and a half hour's drive away from Doria's home in the View Park-Windsor Hills neighbourhood of Los Angeles.
Meghan is extremely close to her mother, Doria
Harry and Meghan's new property even has its own guest house with plenty of space for Doria to stay, so there's every chance she will move in for the first few weeks of the baby's life.
Similarly, Doria was on hand to help out immediately after Archie's birth in 2019, and stayed with the new family in their then-home, Frogmore Cottage.
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