Kevin Sinfield has led the tributes to his "dear friend" and former Leeds Rhinos teammate Rob Burrow who died on Sunday at the age of 41.
Burrow was diagnosed with motor neurone disease (MND) in 2019 and subsequently dedicated himself to raising awareness of the condition and funds for charities along with Sinfield. The pair helped to raise more than £15 million ($19.1m) for MND charities.
"Today was the day that I hoped would never come," Sinfield said in a statement. "The world has lost a great man and a wonderful friend to so so many. You fought so bravely until the end and became a beacon of hope and inspiration, not only for the MND community but for all those who saw and heard your story.
"My love and thoughts go to your beautiful family, Lindsey, Macy, Maya, and Jackson, to your lovely parents Geoff & Irene, sisters Joanne and Claire and your wider family and friends.
"You will continue to inspire me every single day. I have lost a dear friend and I will never forget the special times we shared both on and off the pitch.
"I would always say that you were pound for pound the toughest player I ever played alongside, however since your diagnosis, you were the toughest and bravest man I have ever met.
"The last four and a half years you showed the world what living and loving looked like and this was always done with the biggest smile on your face. I will miss you my little mate."
The Prince and Princess of Wales, William and Kate, also paid their respects to the rugby league legend who represented England and Great Britain during his illustrious playing career.
"A legend of Rugby League, Rob Burrow had a huge heart," the royals said in a post on X. "He taught us, 'in a world full of adversity, we must dare to dream.' Catherine and I send our love to Lindsey, Jackson, Maya and Macy."
The MND Association described Burrow as a "consistent and passionate advocate for people with MND."
"It is testament to the strength of feeling people have for Rob that the support in his name has never wavered," the charitable organisation added.
"The MND Association is incredibly grateful to Rob and his family for helping to raise awareness of MND, and funds for the Association, by sharing the details of their journey and by inspiring so many people both within the MND community and the wider public."
Burrow, who made more than 400 appearances for Leeds, is regarded as one of the best players in the club's history as he won 13 major honours during an illustrious 16-year career.
Leeds' Super League rivals St Helens Saints paid tribute to the scrum-half, with chairman Eamonn McManus saying that Burrow had left an "indelible mark" on the sport.
"I'm sure I speak on behalf of everyone at St.Helens when I express both sorrow on Rob Burrows' passing and the deepest of sympathy for his family and friends," McManus said in a statement.
"His long fight against MND showed the bravery and spirit which he showed always as a rugby league player throughout his career. He was the nemesis of St Helens on so many big occasions but is remembered only as one of the all time greats by all of our supporters: indeed the biggest of little men.
"He has left an indelible mark on our sport. He has also done so much to further the recognition of the terrible disease which afflicted him, and to assist the research which will save the lives of others in the future. He leaves an unforgettable and unmatchable legacy in so many ways."