Kate Middleton’s cancer diagnosis came as a surprise to many, and the Princess of Wales described it as a “huge shock” for both herself and Prince William.

In a video released on March 22, she shared that she was still healing from the “major abdominal surgery” she underwent in January. It was only after that operation that doctors discovered the presence of cancer.

“My medical team advised me to begin a course of preventative chemotherapy, and I’m currently in the early stages of that treatment,” she said.

What kind of cancer does Kate Middleton have?

So far, neither Kate Middleton nor Kensington Palace has revealed the specific type of cancer she’s been diagnosed with.

According to a report by Us Weekly, both Kate and Prince William found out about her diagnosis in late February—the same day William unexpectedly missed his godfather’s memorial service.

“They chose to delay the announcement until their children were on Easter break,” a source shared. “This gave the family time to come to terms with the news privately before the world found out.” The source also added that they have not disclosed the type of cancer.

Dr. George Crawford, a surgeon who has not treated the Princess of Wales, spoke with TMZ and speculated that her cancer might be either uterine or ovarian.

He explained that cancers of the female reproductive system, like uterine or ovarian cancer, often go unnoticed until surgery is performed for what doctors initially suspect are non-cancerous conditions like cysts or fibroids.