Prince William is "extremely proud" of his wife, Kate Middleton, for the "courage and strength" she has shown since her cancer diagnosis and subsequent surgery in January, according to royal sources. The Prince and Princess of Wales have been deeply touched by the outpouring of support from people across the United Kingdom, the Commonwealth, and around the world following Kate's emotional video message on Friday, in which she confirmed she has begun preventative chemotherapy.

A royal source told The Telegraph, "William is extremely proud of his wife for the courage and strength she has shown not just this week, but since her surgery in January. He has always done all he can to protect his family and now more than ever he's focused on ensuring his wife has the privacy she needs to fully recover and that his children are shielded from the understandable interest in the news that has been shared."

In her two-minute video, filmed in the grounds of Windsor Castle on Wednesday, the Princess of Wales described her cancer diagnosis as "a huge shock" and confirmed that she and Prince William had personally broken the news to their children, Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5. She reassured them, saying, "I am going to be ok."

A friend of the Royal Family revealed to The Sunday Times that Kate wrote the speech herself "very quickly," feeling that a video message would be more reassuring than a written statement. "It wasn't really about the drama of the last few weeks, though obviously that has been upsetting. She felt she had to do it because of who she is. It was more that she knows she is a public figure and has a wider leadership responsibility," the friend said.

King Charles III has also expressed his pride in his daughter-in-law's courage for making the public declaration. Buckingham Palace stated, "His Majesty is so proud of ­Catherine for her courage in speaking as she did. Following their time in hospital together, His Majesty has 'remained in the closest contact with his beloved daughter-in-law throughout the past weeks."

On Saturday, William and Kate were seen for the first time since the announcement, boarding a helicopter near their home in Windsor. It is believed they were heading to their Anmer Hall residence in Norfolk, where they plan to spend the Easter school holidays with their children.

A Kensington Palace spokesman said, "The Prince and Princess are both enormously touched by the kind messages from people here in the UK, across the Commonwealth and around the world in response to Her Royal ­Highness' message. They are extremely moved by the public's warmth and support and are grateful for the understanding of their request for privacy at this time."

Leading cancer charities have also issued messages of support following Kate's announcement, with cancer survivors praising her for showing bravery. Michelle Mitchell, CEO of Cancer Research UK, said, "On behalf of everyone at Cancer Research UK, I wish Her Royal Highness a full, swift recovery and return to good health. During this difficult time, it's important that the Princess is given the time and space to focus on her treatment and that we respect the family's privacy."

The Princess of Wales' decision to share her diagnosis has been seen as a testament to her sense of duty and leadership, as she recognizes her role as a public figure. The carefully timed message, released once the couple's children had broken up from school for the Easter break, underscores the Royal Family's commitment to transparency while also prioritizing their privacy during this challenging time.