In a heartfelt selfie-style video filmed near their royal home at Windsor Castle, William said: “Kevin, Catherine and I just want to wish you the best of luck for what’s going to be a very tough week, raising awareness and funds for MND. What you and Rob have achieved is incredible, and your efforts this week are a beautiful tribute to his legacy. I’m sure you’ll be running with him in your mind the entire way.”

William ended the message by saying, “Best of luck from Catherine and me. We’ll be thinking of you all week. Good luck.”

The video’s caption read: “Another incredible feat from a remarkable person. Wishing Kevin Sinfield the best of luck with his latest #7in7 challenge for @mndassoc. We know you’ll do Rob proud.”

Filmed outdoors with a scenic backdrop of towering trees, William appeared dressed smartly in a white shirt and dark grey blazer.

Kevin began his charity work in November 2020 after his former teammate, Rob Burrow, was diagnosed with motor neurone disease (MND).

Kevin pledged to raise £777,777 by running seven marathons in seven days – a target that was reached before his first marathon even started. Over the years, he has raised millions for MND research, a progressive disease that affects nerve cells controlling muscle movement.

Sadly, Rob passed away from the disease on June 2, 2024. William and Kate paid tribute to him, with William describing Rob as “a legend of Rugby League with a huge heart.” He added, “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.”

In September, it was announced that William had written the foreword to a book by Rob’s widow, detailing her life with Rob and his advocacy.

The book, titled Take Care, is set to be released on February 27, 2025.

The announcement was shared on Rob’s official X account, which noted, “I’m honoured to say that the book features a foreword written by HRH Prince William.”

In response, Prince William and Princess Kate shared their support with a blue heart emoji.