Kevin Sinfield is running over 200 miles in a week during what the Prince of Wales called a "fitting tribute" to his late friend Rob Burrow

Prince William is sending well wishes to rugby star Kevin Sinfield amid his latest fundraising efforts.

On Sunday, Dec. 1, the Prince of Wales, 42, shared a rare selfie-style video message on Instagram, in which he praised the efforts of Sinfield, 44 — who will be running over 200 miles in a week as part of what Prince William is calling a "fitting tribute" to Sinfield's late friend and teammate Rob Burrow.

Sinfield will be running "7 ultra marathons" in 7 days across "7 regions," during what's also being called his "Running Home for Christmas" campaign to support Burrow, who died in June at age 41 after being diagnosed with Motor Neuron Disease (MND), according to the MND Association.

Per the BBC, Sinfield will be traveling roughly 230 miles in a week.

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"Kevin, Catherine and I just want to wish you the very best of luck for what's going to be a very grueling week, raising money and awareness around MND," Prince William said in the clip, posted on the Instagram account shared by himself and Kate Middleton.

"What you and Rob have achieved has been incredible and it's a very fitting tribute to his legacy what you're achieving again this week," he continued.

Added William: "I'm sure you'll be running with him on your mind the whole way round. So the very best of luck from Catherine and I. We'll be thinking of you all week."

Prince William shared another message for Sinfield in his video's caption, calling the moment "another remarkable feat for a remarkable human being."

"Wishing Kevin Sinfield the best of luck with his latest #7in7 challenge for [MND Association], we know you’ll do Rob’s memory proud," the royal wrote.

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According to The Independent, Sinfield has raised over $20 million (£16 million) toward MND causes since Burrow was diagnosed in December 2019, two years after the end of his rugby career.

Sinfield's latest effort will kick off in Liverpool on Sunday, Dec. 1, before he makes his way through several towns and villages across England, Wales, Scotland and Northern Ireland, eventually wrapping in Saddleworth, according to the MND Association's website.

Sinfield is currently aiming to raise a total of £777,777 for multiple MND charities in honor of Burrow, who wore a No. 7 jersey.

“We are incredibly grateful for everything Kev has done to support us over the past four years. To be taking on another challenge this year is just incredible," Tanya Curry, the MND Association’s chief executive, said in a statement. “This challenge will be particularly emotional following Rob’s death earlier in the year, but we know the whole MND community will be behind Kev once again, supporting him and keeping him going right to the finish line."

Back in January, Prince William met both Burrow and Sinfield and presented them with CBE honors awarded by King Charles in the New Year's list at Headingley Stadium in Leeds, thanks to their fundraising efforts.

Per the BBC, the Prince of Wales commended Burrow at the time for "all the inspirational work" he'd been behind, while also sharing a "huge congratulations" to Sinfield for his own efforts.

After Burrow's death in June, the Prince of Wales paid tribute to the rugby star on social media, sending wishes to Burrow's wife Lindsey and their three children.

"A legend of Rugby League, Rob Burrow had a huge heart," William said. "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. W."