The royal family have paid tribute to the "humble" rugby legend Doddie Weir.
Doddie has been battling Motor Neurone Disease since 2017 and has led campaigns into research for a cure for the disease ever since, alongside fellow sports stars Rob Burrow and Stephen Darby.
His wife Kathy confirmed his passing in a statement, describing her late husband as an "inspirational force of nature."
Princess Anne, who is a patron of MND Scotland, paid tribute to Doddie.
She said in a statement: "What a sad day, Doug Weir will be greatly missed. He was truly larger than life, determined, generous and humble.
"He transformed people's understanding of MND and funding for research.
"I am so grateful to him and his family for their unselfishness in sharing their experiences. My thoughts and prayers go out to all of his family."
Prince William and Kate Middleton also shared their tribute on Twitter that read: "Doddie Weir was a hero - we are so sad to hear of his passing.
"His immense talent on the pitch as well as his tireless efforts to raise awareness of MND were an inspiration.
"Our thoughts are with all those who loved him. He will be hugely missed across the entire rugby world."
Doddie started his professional career with Newcastle Falcons and spent seven years with the club before joining Border Reivers in his native Scotland.
Doddie, real name George, won 61 caps for Scotland and also represented the British and Irish Lions. He was given an OBE in 2019 for his services to rugby and his campaign work that raised millions.
Weir made an emotional appearance on the pitch before Scotland's defeat to New Zealand earlier this month with players wearing blue and yellow tartan.
Scottish Rugby confirmed his tragic death on social media via a statement from his wife Kathy, who has three sons - Hamish, Angus and Ben.
"It is with great sadness that we announce the death of our beloved husband and father, Doddie," it read.
"Doddie was an inspirational force of nature. His unending energy and drive, and his strength of character powered him through his rugby and business careers and, we believe, enabled him to fight the effects of MND (Motor Neurone Disease) for so many years.
"Doddie put the same energy and even more love and fun into our lives together, he was a true family man. Whether working together on the farm, on holiday or celebrating occasions with wider family and friends, Doddie was always in the thick of it.
"We are lucky to have shared our lives with him and we cherish all those memories; his love and warmth, his support and advice, his quick wit, and his terrible jokes. It is difficult to put into words how much we will miss him.
"MND took so much from Doddie, but never his spirit and determination. He battled MND so bravely, and whilst his own battle may be over, his fight continues through his foundation until a cure is found for all those with this devastating disease.
"Hamish, Angus, Ben and I would like to thank everyone for your support and for respecting our privacy at this difficult time."
His passing comes a week after rugby legend Kevin Sinfield raised over £1.8m for research into MND after completing an ultra-marathon challenge.
