Update, 10/1: In a tweet, Princess Beatrice announced the name of her daughter: Sienna Elizabeth. "We are delighted to share that we have named our daughter Sienna Elizabeth Mapelli Mozzi. We are all doing well and Wolfie is the best big brother to Sienna," she wrote.
Original post: Princess Beatrice and husband Edoardo Mapelli Mozzi are parents again! The princess announced on Monday: "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 added: "Thank you to the Midwife team and everyone at the hospital for their wonderful care."
Beatrice is already stepmother to four-year-old Christopher, known as "Wolfie," Edoardo's son with his ex-fiancee.
In a statement, Buckingham Palace said, "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."
Their daughter will be 11th in line to the throne, and is the 12th grandchild for Queen Elizabeth II. Her arrival comes just a few months after her cousin's: Princess Eugenie gave birth to a baby boy named August in February of this year, so the two will grow up close in age—just like their famously close mothers.