Catherine, Princess of Wales, has said she is "enormously touched" by the support she has received from around the world following her shock announcement on Friday that she is being treated for cancer. 

Catherine, 42, revealed she was undergoing preventative chemotherapy in a video message to the UK, triggering a wave of support from global leaders, family members, media and the public.

"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," Catherine and her husband Prince William, the heir to the throne, said in a statement released late on Saturday.

"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."

The announcement ended weeks of wild speculation about Catherine's health, with many praising her courage and others criticizing the conspiracies that spread over her absence.

The candid disclosure leaves the British monarchy in crisis with King Charles III just weeks ago revealing he was also battling cancer.

Charles -- 17 months into his reign when Buckingham Palace announced in February he would be cancelling all public engagements -- led tributes to his "beloved daughter-in-law".

The ailing 75-year-old monarch spoke of his pride in "her courage in speaking as she did".

Global support

Following other warm words from Prime Minister Rishi Sunak and the White House, British newspapers hailed her courage.

"Kate, you are not alone" read the front page of The Sun. The tabloid said it was "hugely comforting" to hear Kate say she was getting stronger.

"Perhaps the world will now appreciate why so much secrecy surrounded her surgery in January," it added.

The Daily Mail tabloid denounced the "social media trolls who have been peddling disgusting conspiracy theories to explain her absence from public life".

Outside Kensington Palace in London, Nathaniel Taylor, a 24-year-old government worker, said: "I think it's really damning what happened to them, what the media has done, how they've reacted over these past couple of months.

"I think some speculation is inevitable but the lengths people were going to try and make things up it's just (too much). Hopefully people take a look in the mirror."

At Tower Bridge, Sofia, a 19-year-old student who did not give her family name, said she had seen "weird accusations" about the absence and that the true reason was "sad". 

"Obviously it was a much (more) serious matter", she said.

Royal health woes

In her statement, Kate, as the princess is widely known, admitted the diagnosis was a "huge shock" and asked for "time, space and privacy" as she completes chemotherapy. 

In the video -- recorded on Wednesday in Windsor, west of London, where the future queen and king live with their three young children -- she insisted she was "well".

She said it had taken them time to explain the situation to Prince George, aged 10, Princess Charlotte, eight, and five-year-old Prince Louis, "and to reassure them that I am going to be OK".

Buckingham Palace announced on February 5 that tests had identified Charles had "a form of cancer", without giving further details.  

He has cancelled all public engagements except audiences with the prime minister and ambassadors, and worked on official papers while receiving treatment.  

He has been photographed several times since then, and seen attending church. 

"There's no doubt at all that it's a very, very difficult time for the institution of monarchy," royal expert Richard Fitzwilliams told AFP

Kate was last seen at a public engagement on December 25.

Kensington Palace announced on January 17 that she faced up to two weeks in hospital and several months' recuperation following abdominal surgery. 

She was not expected to be ready to return to public duties until after Easter on March 31, a statement at the time said.

'Doing their best'

But Kate disclosed that tests after the operation "found cancer had been present" and that she was now undergoing "preventative chemotherapy".

Kensington Palace said she would return to official duties "when she is cleared to do so by her medical team".

In the meantime, the royal family is facing a staffing crisis with two members facing serious health duties and others stepping back from frontline duties. 

William's younger brother Harry and wife Meghan quit the royal frontline in 2020 and now live in the United States, largely estranged from the family following the acrimonious split.

The king's brother Andrew is also out of commission, stepping down from royal duties in 2019 after a disastrous television interview in which he defended his friendship with the late US sex offender Jeffrey Epstein.