Princess Eugenie has celebrated becoming an aunt by penning a heartfelt message dedicated to her sister Princess Beatrice and new niece.
On Monday night, the 33-year-old announced that her baby girl, whom she shares with husband Edoardo Mapelli Mozzi, 38, was born on Saturday 18 September.
Eugenie took to her personal Instagram page to mark the enormous family milestone and began her post with a congratulatory message for her sister and her brother-in-law.
The 31-year-old royal wrote, "To my dearest Beabea and Edo.
"Congratulations on your new angel. I can't wait to meet her and I'm so proud of you. We're going to have so much fun watching our children grow up. Love Euge."
Eugenie dedicated the rest of her post to her new niece, whose name is yet to be revealed by her parents.
"To my new niece. I love you already and think you're just awesome from the photos. we're going to have so much fun together. Love your Auntie Euge 🥰🥰💕💕😘," gushed Eugenie.
The royal paired her earnest words with a picture of Beatrice and Edoardo posing in front of a waterfall.
Buckingham Palace confirmed the news by sharing an official statement, which read, "The new baby's grandparents and great-grandparents have all been informed and are delighted with the news.
"The family would like to thank all the staff at the hospital for their wonderful care.
"Her Royal Highness and her child are both doing well, and the couple are looking forward to introducing their daughter to her big brother Christopher Woolf."
New mum Beatrice also took to Twitter with a brief statement sharing the news of her daughter's birth.
"So delighted to share the news of the safe arrival of our daughter on Saturday 18th September 2021, at 23.42, at the Chelsea and Westminster Hospital, London," she wrote.
"Thank you to the Midwife team and everyone at the hospital for their wonderful care."
Beatrice and Edoardo welcomed their little bundle of joy just months after celebrating their first wedding anniversary in July.
The pair wed in an intimate surprise ceremony on July 19, 2020, during the coronavirus lockdowns in the UK, after their plans for a big royal wedding were cancelled.
This is Beatrice's first child and the second for Edoardo, who shares his son Christopher "Wolfie" with ex-fiancée Dara Huang, an American architect and designer.
In February of this year, Princess Eugenie also gave birth to her first child with husband Jack Brooksbank, when they welcomed a son named August.