While Eugenie is Her Royal Highness Princess Eugenie of York, it doesn't automatically mean that her son will also inherit a title.
WATCH: Princess Eugenie and Jack Brooksbank welcome baby boy!
In fact, as it stands, Eugenie and Jack's child will have no official title at all.
"As things stand, Princess Eugenie's baby will not have a title, or use the HRH style, because these are passed down the male line and Jack does not have a title," says Royal Editor Emily Nash.
However, the Queen could decide to intervene and give Eugenie’s husband an earldom or issue a Letters Patent amending the rules.
Princess Eugenie and Jack Brooksbank are expecting their first child in 2021
"The Queen could change this, but only by giving Jack a title of his own or changing the rules on inheriting titles by issuing Letters Patent," Emily added.
"He or she will be known as Master or Miss Brooksbank, similar to most other great-grandchildren of the Queen, such as Savannah and Isla Phillips, Mia and Lena Tindall and Archie Mountbatten-Windsor."
Eugenie and Jack welcomed a baby boy on 9 February, Buckingham Palace confirmed.
Eugenie shared this first photo of her son on Instagram
In a statement, the palace said: "Her Royal Highness Princess Eugenie was safely delivered of a son today, 9th February 2021, at 0855hrs at The Portland Hospital. Jack Brooksbank was present. The baby weighs 8lbs 1oz.
"The Queen, The Duke of Edinburgh, The Duke of York, Sarah, Duchess of York, and Mr and Mrs George Brooksbank have been informed and are delighted with the news.
"This is Princess Eugenie and Jack Brooksbank’s first child, The Duke of York and Sarah, Duchess of York’s first grandchild, and the ninth great-grandchild for The Queen and The Duke of Edinburgh. Her Royal Highness and her child are both doing well."
The couple announced Eugenie's pregnancy with this sweet photo
Eugenie and Jack announced their baby news on Instagram last September, posting two photos and writing: "Jack and I are so excited for early 2021..." The pictures showed the happy couple holding up a pair of John Lewis bear slippers, while they happily smiled towards the camera in the second snap.
Buckingham Palace also said in a statement: "Her Royal Highness Princess Eugenie and Mr Jack Brooksbank are very pleased to announce that they are expecting a baby in early 2021.
"The Duke of York and Sarah, Duchess of York, Mr and Mrs George Brooksbank, The Queen and The Duke of Edinburgh are delighted with the news."
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