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The Duke and Duchess of Cambridge are delighted about the arrival of their new niece.

This weekend, the Duke and Duchess of Sussex announced that they welcomed their second child, daughter Lilibet “Lili” Diana Mountbatten-Windsor on Friday, June 4.

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“It is with great joy that Prince Harry and Meghan, The Duke and Duchess of Sussex, welcome their daughter, Lilibet ‘Lili’ Diana Mountbatten-Windsor, to the world,” Lili was born on Friday, June 4 at 11:40 a.m. in the trusted care of the doctors and staff at Santa Barbara Cottage Hospital in Santa Barbara, CA.”

Prince William and Kate Middleton took to Instagram Sunday afternoon to congratulate the entire Sussex family on their new addition.

“We are all delighted by the happy news of the arrival of baby Lili,” the Cambridges wrote in the caption of a post that included a black and white photo of Harry, Meghan, and their son, Archie. “Congratulations to Harry, Meghan and Archie.”

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Other members of the royal family also posted messages of congratulations for the Sussex family on social media.

“Congratulations to Harry, Meghan and Archie on the arrival of baby Lilibet Diana 🎊,” Prince Charles and Duchess Camilla’s Clarence House account posted. “Wishing them all well at this time.”

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“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,” the Queen’s official Instagram account wrote on Instagram along with a photo of Harry and Meghan from their wedding day. “Lilibet is Her Majesty’s 11th great-grandchild.”This content is imported from Instagram. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

This article originally appeared on Harper’s BAZAAR US.