London: Britain’s Princess of Wales Kate Middleton has been diagnosed with cancer and disclosed her illness to the world in a video message.

In an emotional video statement, she revealed that the cancer was detected during a major abdominal surgery at the London Clinic earlier this year.

The 42-year-old princess said she needs to recuperate from the surgery before starting "preventive chemotherapy" as recommended by her medical experts.

The announcement is a huge shock to the royal family, as King Charles and the future queen find themselves battling cancer at the same time.

Rumours and wild conspiracy theories circulating online have fuelled speculation about Kate's medical condition for weeks.

Dressed in a blue and white striped jumper and blue trousers, Kate recorded the video message sitting on a garden bench at Windsor on Wednesday.

She said: “It has been an incredibly tough couple of months for our entire family, but I’ve had a fantastic medical team who have taken great care of me, for which I am so grateful.

“In January, I underwent major abdominal surgery in London and at the time, it was thought that my condition was non-cancerous.

Praising her husband as “a great source of comfort and reassurance”, Kate added: “This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family.

“As you can imagine, this has taken time. It has taken me time to recover from major surgery in order to start my treatment.

“But, most importantly, it has taken us time to explain everything to George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be ok.”

Kate's last official royal engagement was at Christmas when she joined the rest of the family for church at Sandringham.

Following this, she spent two weeks in the hospital in January and was anticipated to take several months to recuperate, with plans to return to official duties after Easter.

Her absence from public view led to rampant speculation about her health, particularly exacerbated when she shared a family photo to commemorate Mother's Day, with her three children.

The photo was retracted by news agencies upon discovery that it had been "manipulated."

The princess later apologised, saying, "Like many amateur photographers, I do occasionally experiment with editing."

According to reports, the controversy left the 42-year-old princess "very sad" that a happy family snap had sparked such chaos.

The shocking news from Kensington Palace will likely put an end to the rumours and speculation, as the princess has requested privacy to allow her family to deal with her condition.

“We hope that you will understand that, as a family, we now need some time, space and privacy while I complete my treatment. My work has always brought me a deep sense of joy and I look forward to being back when I am able, but for now I must focus on making a full recovery.”

Empathising with all those who are also battling cancer, she concluded her statement by saying: “At this time, I am also thinking of all those whose lives have been affected by cancer. For everyone facing this disease, in whatever form, please do not lose faith or hope. You are not alone.”

The duration of Kate's treatment has not been revealed, but it's believed that she might express a desire to attend events as she feels capable, following medical advice.

However, such appearances wouldn't mean a return to full-time duties.

As the news of Kate’s sickness spread, UK PM Rishi Sunak said she has “the love and support of the whole country”.

White House Press Secretary Karine Jean-Pierre told reporters in Washington: “Our thoughts are with the Duchess of Cambridge and her family members and friends during this incredibly difficult time.”