The new arrival is named Ernest George Ronnie Brooksbank, which the 32-year-old Princess explained is a sweet nod to relatives on both Eugenie and Jack's sides of the family.
The royal couple, who already share two-year-old August, announced the news today in the most millennial way - an Instagram post, which unsurprisingly has since gone viral, raking in over 250,000 likes already.
A photo posted by on
"Jack and I wanted to share the news that we had our little boy, Ernest George Ronnie Brooksbank on 30th May 2023 at 8.49 weighing 7.1lbs," the royal couple announced in the Instagram post.
Going on to elaborate on their new arrival's name, the post continued: "He is named after his great great great Grandfather George, his Grandpa George and my Grandpa Ronald."
And going on to acknowledge their eldest son August, they added: "Augie is loving being a big brother already."
The newest member of the Mountbatten-Windsors will reportedly be known by the title "Master Brooksbank", and will now be 13th in line to the throne.
Ahead of Master Brooksbank in the line of succession are: Prince William, Prince George, Princess Charlotte, Prince Louis, Prince Harry, Prince Archie, Princess Lilibet, Prince Andrew, Princess Beatrice, her daughter Sienna Elizabeth, Princess Eugenie and her eldest son August Philip.
The royal family has not yet commented on the happy news, but we will continue to update this story.
Huge congratulations to Princess Eugenie and Jack Brooksbank on their new arrival!
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Jenny Proudfoot is an award-winning journalist, specialising in lifestyle, culture, entertainment, international development and politics. She has worked at Marie Claire UK for seven years, rising from intern to Features Editor and is now the most published Marie Claire writer of all time. She was made a 30 under 30 award-winner last year and named a rising star in journalism by the Professional Publishers Association.
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