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Prince William and Kate Middleton share sweet message about royal baby's arrival

The Duke and Duchess of Cambridge released a royal regram — and an adorable note about their new nephew.
/ Source: TODAY

The newest member of the British royal family arrived in the wee hours of Monday morning, leaving first-time father Prince Harry "over the moon" about the baby boy he now shares with his wife, the former Meghan Markle.

And now other royals have had a chance to react to the happy news.

On Monday night, the Instagram account for Prince Harry's brother, Prince William, and sister-in-law, Catherine, Duchess of Cambridge, reposted the baby's official birth announcement, adding a note of their own.

"The Duke and Duchess of Cambridge are delighted with the news of the birth of The Duke and Duchess of Sussex's son today, and look forward to meeting the latest addition to the family," the brief message read.

William had more to say during an outing in Greenwich Tuesday.

With his wife by his side, the prince said that they're "absolutely thrilled" about their new nephew, who they plan to meet "in the next few days," and that he now welcomes Harry "to the sleep deprivation society that is parenting."

As for the earlier Instagram message, the phrase "The Duke and Duchess of Sussex's son" may seem a little formal for family, but the fact remains that the little one doesn't have a name of his own just yet — at least not one the public knows about.

"Still thinking about names ... The baby's a little bit overdue, so we've had a little bit of time to think about it," Harry told reporters gathered on the grounds of Windsor Castle Monday, adding that the naming process is "the next bit."

If past royal births are any indication, that "next bit" could take a while — as in hours, days, weeks or more. The most recent example would be William and Kate's 1-year-old son, Prince Louis. His parents left the public guessing for four days before they revealed the name of the youngest Cambridge.

The Duke & Duchess Of Cambridge Depart The Lindo Wing With Their New Son
Catherine, Duchess of Cambridge, and Prince William, Duke of Cambridge, depart the Lindo Wing with their newborn son Prince Louis of Cambridge at St. Mary's Hospital on April 23, 2018, in London, England. The duchess safely delivered a boy at 11:01 a.m., weighing 8 pounds, 7 ounces, who is fifth in line to the throne.Samir Hussein / WireImage

But we do know a few other details for sure.

Prince Harry and Meghan, Duchess of Sussex, welcomed their first child to the world at 5:26 a.m. Monday. Their son weighed in at weighed in 7 pounds, 3 ounces.

And according to the baby's proud dad, "This thing is absolutely to die for" — a detail Uncle Will and Aunt Kate should find out for themselves when they meet him.

And they're not the only ones anticipating an introduction to the boy. Grandfather Prince Charles and his wife, Camilla, Duchess of Cornwall, are eager, as well.

"We couldn't be more delighted at the news," Charles told well-wishers in Berlin before his meeting with German Chancellor Angela Merkel, "and we're looking forward to meeting the baby when we return."

Queen Elizabeth also was asked about the newest addition to the royal family. During an awards service Tuesday at Windsor Castle, not far from the home of Harry and Meghan, the monarch was greeted by former Canadian Prime Minister Jean Chrétien.

"Life is good for Your Majesty?" he asked.

She answered it was indeed.

"Congratulations. Another great grandchild! How many of them have you got now?" Chrétien asked, to which the queen replied, "Eight!"

The former prime minister noted she had him beat him by one.

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