Kevin Sinfield was granted Royal approval as he set off on his latest epic mission to raise funds to combat Motor Neurone Disease on Sunday.
Having already raised over £10million for four previous marathon feats, Sinfield is aiming to run more than 230 miles in seven days across all four parts of the United Kingdom.
It is his first fundraising quest since his friend and former Leeds team-mate Rob Burrow passed away at the age of 41 in June.
In a message on social media, the Prince of Wales told Sinfield: “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.
“I’m sure you’ll be running with him in your mind the whole way round.”
England rugby union coach Sinfield was greeted by Merseyside football heroes Peter Reid and John Barnes before starting his first leg in the company of thousands of Father Christmases in the city’s annual Santa Dash.
After finishing the first leg in Wrexham, Sinfield will embark on a gruelling route on Monday, with the second leg going from Gloucester to Bristol.
On Tuesday he goes to Belfast and Wednesday Glasgow, before trips to Hull, Northampton, Leicester and a final leg ending in his home town of Saddleworth.
As of Monday morning, the total raised for Sinfield’s current adventure sat at just over £300,000.