William praised Sir Kevin, who was cheered through York during most recent endurance challenge for the motor neurone disease (MND) community, saying: “The guy is just a machine.”

Sir Kevin Sinfield after he was made a Knight Bachelor at an investiture ceremony at Windsor Castle, Berkshire (Image: Andrew Matthews/Press Association)

“I don’t know how he keeps going, I’m worried about his knees, I’m worried about his hips,” William told BBC Breakfast.

“He’s a top bloke,” William added, “really nice guy, good, honest, kind, decent northerner and I love that about Kevin, that there is no ego with him. He is what you get.”

Sir Kevin Sinfield sets off from Bishopthorpe Palace with England Rugby Union head coach Steve Borthwick on day three of the 7 in 7: The Grand Finale 2026 Challenge, Bishopthorpe Palace - DIY Kitchens Stadium (Image: Mike Egerton/PA Wire)

Sir Kevin, who has raised millions for charity, received a knighthood for his services to the MND community, as well as for services to league and union rugby.

The Prince and Princess of Wales recently surprised Sir Kevin in Wakefield as he completed the third day of his final 7 in 7 running challenges, having set off earlier that day from Bishopthorpe Palace.

The Prince and Princess of Wales surprise Sir Kevin Sinfield (second from right) at the end of day three of his 7 in 7: The Grand Finale 2026 Challenge, at the DIY Kitchens Stadium, the home of Wakefield Trinity (Image: Mike Egerton/PA)

Sir Kevin’s challenge involved completing an ultra-marathon every day for seven days.

The fundraiser was inspired by his former Leeds Rhinos teammate Rob Burrow, who died in 2024 after living with MND for four-and-a-half years.

William said he had also written a letter to the Burrow family.

“Everyone grieves differently and every circumstance is different, so you need to take your time over it,” he said.

“It’s always better to say something around grief than it is to ignore it.”

Speaking about receiving his knighthood, Sir Kevin previously said he was “massively humbled by the whole experience” and “very proud to accept it on behalf of the MND community and their families”.

The 46-year-old said William, who presented Sir Kevin and Mr Burrow with CBEs at Headingley Stadium in 2024, had been “fantastically supportive” of their campaign.

Sir Kevin told the Press Association: “I think he champions pulling communities together and I have seen how the MND community have come together on the back of Rob’s diagnosis and several other high-profile sportspeople over the last six or seven years.

“So, his support and, obviously, Princess Catherine’s as well, they’ve been wonderful and bring a real credibility to what we’re trying to do.”

Sir Kevin was greeted by the Princess Royal as he arrived at the University of York on the second day of his 7 in 7: The Grand Finale challenge last month.

At the University of York, Sir Kevin was joined by members of the MND community, including former England rugby captain Lewis Moody who was diagnosed with MND last year, in running an “extra mile”.

Sir Kevin told the gathered crowd from the MND community that the extra mile event was the “best part” of the challenge.

“We just get the chance to come together. To fight together. To run together. To walk together,” he said.