Meanwhile, Lili's grandparents, Prince Charles and Camilla Parker-Bowles, also shared their reaction to the sweet news via the official Clarence House Instagram.
Posting a throwback photo from the Sussex's tour of South Africa, the caption read, "Congratulations to Harry, Meghan and Archie on the arrival of baby Lilibet Diana 🎊Wishing them all well at this time".
The Queen was similarly delighted by the arrival of her 11th great-grandchild.
Upon confirmation of the news, the official royal family Instagram account shared a gorgeous shot from Harry and Meghan's wedding day to congratulate the couple on their latest addition.
The post read, "Congratulations to The Duke and Duchess of Sussex on the birth of Lilibet Diana! The Queen, The Prince of Wales and The Duchess of Cornwall and The Duke and Duchess of Cambridge are delighted with the news."
Royal fans were equally delighted with the news in the comments section.
"Congratulations!!! Hold her tight, life is so precious ❤️ and such a beautiful choice of names too," one user wrote.
"Congratulations to Her Majesty on another beautiful great-grandchild!!! ❤️❤️," another penned.
"Wonderful news and a beautiful name honouring both Her Majesty and Princess Diana. 💖" a third added.
Harry's cousin Princess Eugenie was also among the well-wishers, taking to her Instagram story to share her congratulations for her relatives.
"Congratulations dear cousins. We couldn't be happier for you all," Eugenie wrote.
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