Attendees included 11-year-old paraplegic boy Ted Haslam, whom Kate, 45, met when she completed the arduous challenge in June.
The Princess of Wales hosted her fellow Three Peaks Challenge fundraisers at Windsor Castle last week as a 'powerful reminder' that 'recovery is rarely a journey we make alone'.
Kate, 44, completed the gruelling hike across the UK's highest mountains in June to raise funds for the Royal Marsden Hospital in central London, where the future queen underwent cancer treatment before announcing she was in remission in January 2025.
A video from the tea party was posted on the Prince and Princess of Wales's official Instagram story today, with Kate recognising the 'importance of the people who walk alongside us'.
Her message read: 'It was a pleasure to welcome other Three Peaks Challenge participants and their families to Windsor Castle.
'Behind every summit was a personal story of resilience, determination and hope. Listening to their experiences of the challenge and their reasons for taking it on was a powerful reminder that recovery is rarely a journey we make alone, and of the importance of the people who walk alongside us along the way. C'
One person who attended the tea party was 11-year-old paraplegic Ted Haslam, whom the Princess met on Ben Nevis in Scotland as he was pushed and carried by 15 friends and relatives, including his father Pete.
Albie-Junior Thomas, nine, who was raising funds for his local football club, was also on the guest list after he became the youngest amputee to conquer the three peaks within 24 hours this August. He was born without a fibula, and his foot was amputated when he was a toddler.
Other guests included Sean McCormick, who took on the challenge to raise money for his friend's nephew, who had been diagnosed with cancer, and Trish Patterson.
The Princess of Wales hosted a tea party at Windsor Castle for her fellow Three Peaks Challenge participants
Ms Patterson became the fastest woman to complete the mammoth challenge of scaling the three highest mountains in Scotland, England and Wales on foot a few days after Kate's journey.
By running between each climb, the 41-year-old mother from Hythe in Hampshire broke the existing record by nine hours, clocking a total time of five days and 21 hours.
During the adventure, the princess crossed paths with schoolboy Ted, who was raising money for Molly Olly's Wishes, a charity which supports children with serious illnesses.
She donated to Ted’s cause on JustGiving, leaving the message: 'One of the real highlights of the Three Peaks Challenge was meeting inspiring people like you along the way.
'Huge congratulations to Ted, Pete and the entire team for raising money for such a wonderful cause.'
During a recent visit to Royal Marsden in London, the future queen heard how the money she raised is being used to build a new specialist centre for Holistic Wellbeing.
Hospital chairman Sir Douglas Flint thanked her for the fundraising efforts as Kate modestly said it was her way of ‘giving back’ for all the ‘incredible’ care she has received on her own cancer journey.
The future Queen heard stories of 'resilience' from those who decided to take on the Three Peaks Challenge
Ted Haslam (right) met the Princess when they completed the challenge in June, while Albie-Junior became the youngest amputee to conquer the three peaks in August
The princess in conversation with Albie-Junior, who was born without a fibula, and his foot was amputated when he was a toddler
A video from the royal tea party last week was posted on the Prince and Princess of Wales's official Instagram story this morning
She smiled and said: ‘This was my small way of being able to give back and say thank you to you. I had incredible care here and support from a huge team and I'm really really grateful on a personal level.
'But also the holistic care, the treatments and therapeutic support alongside the clinical pathway is so important. It makes a big difference.
‘The impact of nature, the impact of good nutrition, good ongoing support around you when it's really difficult to manage the trials and tribulations of medical treatments... it makes a big difference.
'It made a big difference to me and it made a huge difference to lots of patients who I've spoken to. Thank you and well done. I think it will be transformative not only for patients but for families too.’
The future queen secretly undertook the gruelling physical charity climb back in June, with her proud family meeting her at the last stop at the base of Snowdon, the highest peak in Wales. She had also scaled Ben Nevis and Scafell Pike.
The Three Peaks Challenge sees participants attempt to scale Ben Nevis, Scafell Pike and Yr Wyddfa in Wales within 24 hours.
It has a total walking distance of 23 miles (37km), an ascent of 3,064m (10,052ft) of vertical climbing and a driving distance between the peaks of approximately 462 miles.
A picture released by Kensington Palace showed Catherine beaming with delight at the summit of Ben Nevis, dressed in cold weather walking gear.
In a personally penned message, the Princess – who was diagnosed with an unspecified cancer following major abdominal surgery and underwent gruelling chemotherapy, finally revealing she was in remission a year later – said: ‘Every year, hundreds of thousands of people in this country hear the words no one wants to hear.
'What follows is a path that tests every part of who we are: physically, emotionally, psychologically and spiritually. The challenges ripple outwards, touching families, friendships, work and the quiet moments we spend alone with our thoughts.
‘Cancer doesn’t just affect the body. It changes how you think and feel and profoundly affects every aspect of life. I know this personally, and that the journey through and beyond treatment requires more than medicine alone.
‘I have taken on the National Three Peaks Challenge, not simply as a physical endeavour but as a chance to explore life beyond diagnosis and to give something back.
'The Royal Marsden is a place that holds great meaning for me and whose care and expertise are life-changing for so many people.’
Kate (centre, wearing a baseball cap) poses for a group photo next to Ted during the Ben Nevis climb
The royal carried out the challenge solo, supported en route by Mountain Rescue, and was greeted at the end by William, her children George, Charlotte and Louis
The Princess' brother James Middleton (right) and their parents, Carole and Michael Middleton, were also waiting to celebrate with Kate after the challenge
Kate giving her daughter, Princess Charlotte, a big hug
The princess said she was keen to raise awareness for the ‘deeper impact of serious illness’ and, particularly, the importance of holistic healthcare, which she says complements clinical pathways and ‘support patients’ ability to maintain their wellbeing, resilience and quality of life during an exceptionally difficult time’.
She is keen to enable more people nationwide to access the kind of personalised support ‘that can help make a meaningful difference during and after medical treatment’.
‘Healing, whether personal or collective, is not just about fixing what is wrong. It is about finding balance in how we live,’ she said.
‘Together, we can stand alongside everyone navigating life with cancer, ensuring no one faces this disease feeling unseen or unsupported. Please know you are not alone’.
The royal carried out the challenge solo, supported en route by Mountain Rescue, and was greeted at the end by William, her children George, Charlotte and Louis, her parents Carole and Michael Middleton and brother James.