With Prince Harry and Meghan Markle have announced the arrival of their second child, named Lilibet Diana.
Now, many royal fans are wondering what surname the baby will take.
Harry and Meghan welcome Lilibet Diana
Making the announcement on their Archewell website, the couple said Lilibet “Lili” Diana Mountbatten-Windsor, who was born on Friday, 4 June at Santa Barbara Cottage Hospital in Santa Barbara, was "more than we could have ever imagined" and is now "settling in at home".
In a message of thanks from Meghan and Harry on the Archewell website, they said: "On June 4, we were blessed with the arrival of our daughter, Lili.
"She is more than we could have ever imagined, and we remain grateful for the love and prayers we’ve felt from across the globe.
"Thank you for your continued kindness and support during this very special time for our family.”
The couple asked anyone wishing to send a present to support organisations working for women and girls.
Royal fans have taken to Twitter to share their confusion over Harry and Meghan surnames, as well as those of their children, with one user writing: "It’s Meghan Markle and Harry what? What’s his last name? I’m gonna start calling him Harry Markle."
Does the royal family even use a surname?
According to the royal family's website, the royal family can be known by both the name of the royal house and by a surname, but they are not always the same. Many of them don't even use a surname at all.
The royal family didn't actually have a surname until 1917, instead choosing to go by the name of the house they belonged to - for example, Wales, Cambridge or Sussex.
However, in 1917, King George V stated "all descendants in the male line of Queen Victoria, who are subjects of these realms, other than female descendants who marry or who have married, shall bear the name of Windsor".
The Queen later confirmed this in 1952, however, in 1960, she and the Duke of Edinburgh decided their descendants who do not use HRH and have the title of prince or princess, or women who married, would use the surname Mountbatten-Windsor in honour of Prince Philip's surname.
What surname do Prince William and Prince Harry use?
The royals do use Mountbatten-Windsor, however, they often use a variation of names. When Prince William and Prince Harry served in the military, they used the surname Wales, because their father was the Prince of Wales.
Similarly, Princess Eugenie and Princess Beatrice use the surname York, as their father is the Duke of York.
When it comes to William's children Prince George, Princess Charlotte and Prince Louis, their birth certificates all say their surnames are Cambridge, after their father's assigned dukedom.
So, what surname do Prince Harry's children use?
As Prince Harry and Meghan's children don't have titles, they will be known as a Lord or Lady and use the surname Mountbatten-Windsor as the Queen and Prince Philip decided in 1960.
This could change, should the Queen issue a Letters Patent to give Prince Harry's children the attribute of royal highness as she did in December 2012 for Prince William's children.
At the time, she said: "All the children of the eldest son of the Prince of Wales should have and enjoy the style, title and attribute of royal highness with the titular dignity of Prince or Princess prefixed to their Christian names or with such other titles of honour."
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