Kate Middleton, Princess of Wales, announced on Friday that she has cancer and is undergoing chemotherapy.

The official Twitter account of the Prince and Princess of Wales posted a video of Kate, in which she said: "I wanted to take this opportunity to personally thank you for all the wonderful messages of support and for your understanding during my recovery from surgery. It has been a very difficult two months for our whole family, but I had a wonderful medical team who took great care of me and I am very grateful to them. In January, I underwent major abdominal surgery in London, and at that time, it was believed that my condition was not cancerous."

She added: "The surgery was successful, but the tests conducted after the operation showed the presence of cancer. Therefore, my medical team advised me to undergo a course of preventive chemotherapy, and I am now in the early stages of this treatment. This was, of course, a great shock, and William and I have done everything we can to handle and manage this matter privately for our little family. As you can imagine, this took time. It took some time to recover from major surgery before starting my treatment, but more importantly, it took time to explain everything to George, Charlotte, and Louis in a manner appropriate for them and to reassure them that I will get through this."

She continued: "As I told them, I am fine and getting stronger every day by focusing on the things that will help me heal mentally, physically, and spiritually. Having William by my side is also a great source of comfort and reassurance, as is the love, support, and kindness shown by so many of you. That means a lot to both of us. We hope you 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 happiness, and I look forward to returning when I am able. But for now, I need to focus on a full recovery. At this time, I also think of all those whose lives have been affected by cancer. To everyone facing this disease, in any form, please do not lose faith or hope. You are not alone."

The video came weeks after speculation spread on social media about her whereabouts and health since she was admitted to the hospital in January for an unspecified abdominal surgery.

Kate, 42, had not been seen publicly since Christmas until a video appeared this week of her with her husband, Prince William, the heir to the throne, walking from a farm shop near their home in Windsor.

Kensington Palace provided little detail about Kate's condition except to say that it was not cancer-related, that the surgery was successful, and the recovery would keep the princess away from public duties until April.

This news represents another shock to the royal family since last month's announcement that King Charles III is being treated for an unspecified type of cancer discovered during surgery for benign prostate enlargement.

Charles, 75, has withdrawn from public duties while undergoing cancer treatment, although he has frequently been seen in photos holding meetings with government officials and dignitaries, and even attending church.

Meanwhile, Kate remained out of the public eye, leading to weeks of speculation, and the palace tried to quell rumors by posting a photo of her on Mother’s Day in the UK surrounded by her three smiling children, which backfired when the Associated Press and other news agencies withdrew the photo because it was manipulated.

Kate issued a statement the following day admitting she loved the "editing experience" and apologized for "any confusion" caused by the photo. But this did little to suppress the speculation.

Even footage published by The Sun and TMZ showing Kate and William shopping sparked a new wave of rumors, with some investigators refusing to believe the video actually showed Kate at all.

Earlier this week, the UK privacy watchdog said it was investigating a report that staff at the private London hospital where she was treated tried to spy on her medical records during her abdominal surgery.

Kate Middleton, who married William in a fairy-tale wedding in 2011, has boosted the popularity and appeal of the British monarchy worldwide more than any monarch since Princess Diana.

The princess is the eldest of three children raised in a wealthy neighborhood in Berkshire, west of London. The Middleton family has no aristocratic background, and the British press often referred to Kate as "from the common people" marrying into the royal family.

Kate attended the all-girls private Marlborough College and then the University of St Andrews in Scotland, where she met William around 2001. Initially friends and housemates, their relationship became public when they were photographed together on a ski holiday in Switzerland in 2004.

Kate graduated in 2005 with a degree in art history and an emerging relationship with the prince.