King Charles said he 'remained in the closest contact' with Kate Middleton while they were in the hospital together

• Kate Middleton and King Charles are sticking together through their battles with cancer.
• A Buckingham Palace spokesperson said the king has been in close contact with Kate the past few weeks.

King Charles III is staying close with Kate Middleton as both royals grapple with cancer.

The Princess of Wales announced in an emotional video message posted to Instagram on Friday that she has been diagnosed with cancer and is going through chemotherapy.

Just last month, King Charles was diagnosed with cancer after undergoing a prostate procedure.

The king and princess were both treated during the same period at The London Clinic in January, according to the BBC.

The king "remained in the closest contact with his beloved daughter-in-law throughout the past weeks," a Buckingham Palace spokesperson said, per the BBC, adding that he and his wife, Queen Camilla, "will continue to offer their love and support to the whole family through this difficult time."

"This of course came as a huge shock," Kate, 42, said in her video message, which was filmed on Wednesday by BBC Studios. "And William and I have been doing everything we can to process and manage this privately for the sake of our young family."

Kate explained that the diagnosis followed a major abdominal surgery she had in January.

"As you can imagine, this has taken time," Kate said in the video. "It has taken me time to recover from major surgery in order to start my treatment."

The Buckingham Palace spokesperson added that King Charles is "so proud of Catherine for her courage in speaking as she did," according to People.

The princess did not reveal the stage or type of cancer she's been diagnosed with and asked for privacy for her and her family during this time.

"I am well and getting stronger every day by focusing on the things that will help me heal: in my mind, body, and spirits," Kate said in her video message. "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. It means so much to us both."

Kate's announcement comes after months of speculation, including wild conspiracy theories, on her whereabouts following her surgery.