King Charles said he is "so proud" Princess Kate Middleton spoke up to announce her cancer diagnosis.
The 75-year-old monarch is "so proud of Catherine for her courage in speaking as she did," the Associated Press reported, citing a statement from Buckingham Palace.
Charles has remained in "closest contact with his beloved daughter-in-law" as she continues to navigate the disease, the palace said.
The pair were hospitalized at the same time, earlier this year.
In a video shared Friday, the princess, 42, revealed she has been undergoing preventative chemotherapy after the shocking diagnosis.
The confirmation of her cancer comes two months after Kate underwent major abdominal surgery, prompting a whirlwind of public speculation over her health. At the time, her medical team thought her condition was noncancerous, but further testing showed cancer was present, she said.
She did not elaborate on her specific type of cancer.
"It has been an incredibly tough couple of months for our entire family," the princess admitted.
"I'm getting stronger every day by focusing on the things that will help me heal in my mind, body, and spirits. Having William by my side is a great source of comfort and reassurance too, as is the love, support and kindness that has been shown by so many of you," said Kate.
She and Wiliam share three children: Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5.
The couple wed in Westminster Abbey in 2011.
The news of Kate's cancer comes one month after Charles revealed his own battle with the disease.
