(NEXSTAR) — Catherine, Princess of Wales, revealed Friday that she has been diagnosed with cancer and is undergoing chemotherapy.

In a recorded video message, Princess Kate addressed the public directly after months of rumors about her condition. Kate, 42, was admitted to the London Clinic for abdominal surgery in January. Since then, she has largely been out of the public eye.

At the time of the surgery, Kate said Friday, her condition was thought to be non-cancerous, but tests after the fact revealed cancer cells were present.

“My medical team, therefore, advised that I should undergo a course of preventative chemotherapy, and I am now in the early stages of that treatment,” she said in the released video.

Kate said she needed time to recovery from the surgery, start cancer treatment, and talk to her children about her condition.

“It has taken us time to explain everything to George, Charlotte and Louis in a way that’s appropriate for them and to reassure them that I’m going to be OK,” she said. “We hope that you’ll understand that as a family, we now need some time, space and privacy while I complete my treatment.”

She also thanked the public for their support and understanding.

The news is another shock for the royal family since the announcement last month that King Charles III was being treated for an unspecified type of cancer that was caught while undergoing a procedure for a benign enlarged prostate.

Charles, 75, has withdrawn from public duties while he has cancer treatment, though he’s appeared frequently in photos carrying on meetings with government officials and dignitaries and was even seen going to church.

Kate, on the other hand, had been out of view, leading to weeks of speculation and gossip. Attempts to put rumors to bed by releasing a photo of her on Mother’s Day in the U.K. surrounded by her three smiling children backfired when The Associated Press and other news agencies retracted the image because it had been manipulated.

Kate issued a statement the next day acknowledging she liked to “experiment with editing” and apologizing for “any confusion” the photo had caused.

The former 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 royal since Princess Diana.

The princess is the oldest of three children brought up in a well-to-do neighborhood in Berkshire, west of London. The Middletons have no aristocratic background, and the British press often referred to Kate as a “commoner” marrying into royalty.

Kate attended the private girls’ school Marlborough College and then University of St. Andrews in Scotland, where she met William around 2001. They were friends and housemates at first, then their relationship came to be in the public eye when they were pictured together on a skiing holiday in Switzerland in 2004.

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

The Associated Press contributed to this report.