Henry Worsley died Sunday in a hospital in Chile from "complete organ failure" after falling ill just 30 miles from the intended end of his trek in the footsteps of explorer Sir Ernest Shackleton.
William, 33, who was patron of the expedition, said that he and brother Prince Harry, 31, were "sad to hear of the loss.”
Vowing to make sure Worsley’s wife and two children receive the support "they need at this terribly difficult time," William said, "He was a man who showed great courage and determination and we're incredibly proud to be associated with him."
"Even after retiring from the Army, Henry continued to show selfless commitment to his fellow servicemen and women by undertaking this extraordinary Shackelton solo expedition on their behalf," the prince continued.
The trek had raised more than $150,000 for the Endeavour Fund that aids the recovery of former servicemen and women by inspiring new challenges.
"We have lost a friend, but he will remain an inspiration to us all, especially those who benefit from his support to the Endeavour Fund,” William added.
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Worsley, 55, had walked 913 miles unsupported in extreme weather conditions when he became ill. He was flown to a hospital in Chile by Antarctic Logistics & Expeditions, where he was found to be suffering from exhaustion, dehydration and bacterial peritonitis, a press statement from the organizers says.
The former Army officer is survived by his wife, Joanna, and two children, Max and Alicia. His wife said in a statement, "It is with heartbroken sadness I let you know that my husband Henry Worsley has died following complete organ failure; despite all efforts of ALE and medical staff at the Clinica Magallanes in Punta Arenas, Chile."
"Henry achieved his Shackleton Solo goal of raising over $140,000 for the Endeavour Fund to help his wounded colleagues, and he nearly completed the first unsupported crossing of the Antarctic landmass – a crossing made under exceptionally difficult weather conditions to mark the 100th anniversary of his lifelong hero, explorer Sir Ernest Shackleton’s Endurance expedition," his wife continued.
"On behalf of myself and family, I wish to thank the many hundreds of you who have shown unfailing support to Henry throughout his courageous final challenge and great generosity to the Endeavour Fund. Donations now total over $150,000."
David Beckham joins Prince William in paying tribute to Worsley. The former soccer star took to Instagram to express his condolences.
No words can describe the sadness of the loss of Henry. I was lucky enough to have met Henry on my way out to the Antarctic. I asked if I could use his Union Jack for a picture, he kindly leant it to me and I could feel how special this was to him. I was so honoured that he had done this for me... A man that has served our country for so many years and a man that talked about his family with so much pride... Our thoughts are with Henry's family at this time
"No words can describe the sadness of the loss of Henry," Beckham wrote. "I was lucky enough to have met Henry on my way out to the Antarctic. I asked if I could use his Union Jack for a picture, he kindly leant it to me and I could feel how special this was to him. I was so honored that he had done this for me... A man that has served our country for so many years and a man that talked about his family with so much pride... Our thoughts are with Henry's family at this time."
In his last dispatch, Worsley outlined his mission: “Having been a career soldier for 36 years and recently retired, it has been a way of giving back to those far less fortunate than me.
"The 71 days alone on the Antarctic with over 900 statute miles covered and a gradual grinding down of my physical endurance finally took its toll today, and it is with sadness that I report it is journey’s end – so close to my goal."