Prince William, Kate Middleton Officially Named Prince And Princess Of Wales By King Charles

Prince William and Kate Middleton are officially the Prince and Princess of Wales.

On Friday, King Charles III made the announcement as he addressed the United Kingdom for the first time since his mother Queen Elizabeth II died at the age of 96 Thursday.

Prince William and Middleton changed their social media accounts to reflect their new royal titles.

Initially, they changed their Instagram, Twitter and YouTube handles to Duke and Duchess of Cornwall and Cambridge. But following Charles' first speech as King, the couple updated their social media to show they will now be known as the Prince and Princess of Wales.

"Today, I am proud to create him Prince of Wales, Tywysog Cymru, the country whose title I have been so greatly privileged to bear during so much of my life and duty," King Charles said Friday, according to Page Six.

He continued, "With Catherine beside him, our new Prince and Princess of Wales will, I know, continue to inspire and lead our national conversations, helping to bring the marginal to the center ground where vital help can be given."

An unnamed royal source told Page Six that William and Kate "are focused on deepening the trust and respect of the people of Wales."

"Over time Prince and Princess of Wales will approach their roles in the modest and humble way they've approached their work previously," the source added. "The new Princess of Wales appreciates the history associated with this role, but will understandably want to look to the future as she creates her own path."

Kate is the first royal to use the title Princess of Wales since the death of her late mother-in-law, Princess Diana.

While Charles was often referred to as the Prince of Wales in the past, his second wife Camilla, now Queen Consort, chose not to be known as the Princess of Wales as it was associated with his first wife. Instead, Camilla went by the Duchess of Cornwall.

Several royal fans shared on social media their reactions to William and Kate taking on the titles.

"The Duke and Duchess of Cambridge two days ago. The Duke and Duchess of Cornwall and Cambridge yesterday. The Prince and Princess of Wales today. Just marveling at how fast things are changing. Even if I intellectually knew it would happen, it's still quite something to experience," one person tweeted.

"Catherine is now Her Royal Highness the Princess of Wales. I can't think of a more deserving person," another wrote.

"The new Prince and Princess of Wales, ladies and gentlemen," a third fan tweeted alongside a photo of William and Kate. "Sadly, the titles came because a much-beloved woman passed away, but still, I'm happy about them being the Prince and Princess! They'll continue to do a wonderful job, and I'm excited to continue to support them."

Charles will embark on a tour of the U.K. in the days leading up to Queen Elizabeth II's funeral, which is reportedly part of the U.K. government's 10-step "Operation London Bridge" plan. The Queen's funeral will be held 10 days after her death, Page Six reported, citing "leaked documents."

Royal author Tina Brown told Page Six that she believes King Charles will be a good monarch.

"I actually think he's going to come into his own," Brown said. "I think he's going to be a good king."