Kate Middleton & Her Brother James Seem Closer Than Ever After Her Cancer Diagnosis

Princess Catherine has always been someone who loves to exercise, and in 2026, she proved that it's possible to continue doing the things you enjoy after putting cancer in its place. Kate Middleton took on a grueling physical challenge, while shining a light on the "deeper impact" of cancer, when she took part in the National Three Peaks Challenge in June 2026. The beloved royal did so in support of The Royal Marsden Cancer Charity, but notably, she wasn't alone. Younger brother James Middleton was right by her side, offering his support. Kate Middleton's close relationship with James has been on full display since her cancer diagnosis in 2024. 

Shortly after Catherine's public announcement, James took to Instagram to post a snap of the two of them as kids, sweetly captioned: "Over the years, we have climbed many mountains together. As a family, we will climb this one with you too." The siblings quite literally climbed a mountain during the Three Peaks Challenge, and they were even spotted holding hands in one adorable moment. A hiker who was with their group as they came down from Mount Snowdon in Wales shared a clip on Instagram Stories showing the Middletons making their way down the steep slope with their hands intertwined. 

James openly discussed how he and his family were supporting Catherine on her cancer journey in a handful of interviews. "We are certainly a close family that goes through things together," he told Hello! magazine in 2024. During a chat with The Times, the following year, James explained how he offered his unconditional support to Catherine: "That's the simplest way of really demonstrating love. You can do it in all these various fancy ways but actually, you know, it is just generally being there."

James Middleton is clearly the kind of brother everyone wants to have, but Princess Catherine is also a great sister. James Middleton has weathered plenty of tragedy, and through it all, the Princess of Wales was there when he needed her the most. The author has spoken candidly about his struggle with depression, and how his family helped him get through it. "I'm incredibly fortunate to have my two sisters, not just as siblings, but as friends," James gushed to The Mirror in 2025. "They've seen me at my best and at my lowest, and they've always been there when I've needed them." 

That doesn't mean they don't sometimes have their differences, but according to James, if you work on your relationships with your siblings, "It's one of the most powerful bonds there is." Catherine's strength, as well as that of his other sister, Pippa Middleton, and their mother, Carole Middleton, helped him get out of the dark pit of depression. They were incredibly supportive; in fact, both sisters attended therapy sessions with him. As James told The Times, "Having them there meant that I knew I was surrounded by people that truly understood what I was going through." 

Likewise, in an op-ed the entrepreneur penned for the Daily Mail in 2019, he shared that Catherine's work with herself and Prince William's mental health-focused charity, Heads Together, inspired him to share his story. James also made it clear that his sister's fame, which also affects him, had little to do with his depression. "People have asked me if my public profile has made it harder for me... But I wouldn't have found a voice or an outlet for my story if it hadn't been for the people I'm related to," he reasoned.