James Middleton is celebrating his “darling sister” Kate with a beautiful tribute after joining her on her Three Peaks Challenge for the Royal Marsden Cancer Charity 💙⛰️ "Two years ago, I told you we'd climb this mountain together," wrote James, 39, revealing the touching promise they made while Kate, 44, was in hospital and reflecting on "the incredible healing power that nature can have for both the body and the mind." After praising her "strength, resilience, and determination," as well as her devotion as a mother, wife, daughter and sister, he ended with a simple loving message: "Keep being exactly who you are” 😭 📸: The Prince and Princess of Wales #katemiddleton #royalfamily #cancer