Charles Spencer Shares Support for Kate Middleton amid Cancer Diagnosis: 'Incredible Poise and Strength'

The 9th Earl Spencer, 59, posted his support for the Princess of Wales on Instagram on Saturday

Charles Spencer is voicing his support for Kate Middleton after she shared her cancer diagnosis on Friday.

On Saturday, the younger brother of the late Princess Diana, 59, praised the Princess of Wales following her announcement that she has cancer and is receiving treatment, which came in a video released on Friday.

“Incredible poise and strength,” the 9th Earl Spencer, uncle to Prince William and Prince Harry, wrote in an Instagram post alongside a screenshot from the video shared by Kate on social media.

On Friday, Princess Kate appeared in an emotional video posted on Instagram as she revealed that post-operative tests from her abdominal surgery in January "found cancer had been present.” Kate, who began a course of preventative chemotherapy in late February, explained that she and Prince William needed time to tell their children Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5, of her diagnosis before the public announcement.

Related: King Charles, Who Has Cancer, 'So Proud' of 'Beloved Daughter-in-Law' Kate Middleton amid Her Cancer Diagnosis

Members of the princess’ family have rallied around in support of her following her announcement of her cancer diagnosis.

King Charles, who is also undergoing cancer treatment, spoke of “how proud” he is of his daughter-in-law.

The King, 75, is "so proud of Catherine for her courage in speaking as she did," a Buckingham Palace spokesperson told PEOPLE.

In January, King Charles and Princess Kate were both hospitalized at The London Clinic. The monarch has "remained in the closest contact with his beloved daughter-in-law throughout the past weeks," the spokesperson added. Both King Charles and Queen Camilla "will continue to offer their love and support to the whole family through this difficult time."

Kate’s younger brother James Middleton, also shared a touching message of support as he posted a never-before-seen photo of the pair as children on Instagram.

"Over the years, we have climbed many mountains together. As a family, we will climb this one with you too ⛰️❤️," the 36-year-old wrote in the caption as the two could be seen in the photo wearing backpacks while standing together in front of a mountainous backdrop.

The Princess of Wales is the eldest of her three siblings, which also includes her sister Pippa Middleton. The trio’s parents are Michael and Carole Middleton, live near Kate in the village of Bucklebury and have been a source of strength for Kate since her surgery.

On Friday, Meghan Markle and Prince Harry also shared their support for their sister-in-law in a statement.

Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

"We wish health and healing for Kate and the family, and hope they are able to do so privately and in peace," the Duke and Duchess of Sussex shared with PEOPLE on Friday.

Prince Harry, 39, and Meghan, 42, were last seen together with Princess Kate and Prince William, 41, as the foursome stepped out for a surprise walkabout as they greeted the public in Windsor after the death of Queen Elizabeth in September 2022.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.