Prince William revealed he "couldn't walk for a week" following some of his pre-Coronation exploits.
He admitted his struggle while carrying out an investiture ceremony at Windsor Castle, where he handed ex-England striker Luther Blissett an OBE.
The former player was being recognised for his services to football and his charity work, with William confiding in him he still enjoys playing in 11-a-side games.
And after receiving his award, the former Watford player discussed what he and the Prince of Wales talked about - and how he gave him an invitation.
He explained: "We had just a couple of little words. I did ask him if he would love to come and join us on the (Watford former) players club and he said yes, he would love to.
"He said he was playing (football) last week and he said he couldn’t walk for a week afterwards. He says he still plays 11-a-side."
Blissett was one of the most prominent black English footballers in the 1970s and 80s and he was the first black footballer to score a hat-trick for England.
He is now patron of Sporting Memories, which uses the power of sport to unlock memories in people with dementia, depression or loneliness.
The 65-year-old said he hoped his award would open doors to allow him to take his work with former football players further and they are currently also working with veterans.
William is known to be a keen football fan, supporting Aston Villa, and is also president of the Football Association.
The heir to the throne has frequently been seen at Villa games and attended the 2015 FA Cup Final which they played in, revealing the origins of his connection to the club ahead of the game.
"A long time ago at school I got into football big time. I was looking around for clubs. All my friends at school were either Man United fans or Chelsea fans and I didn’t want to follow the run of the mill teams," he told the BBC.
"I wanted to have a team that was more mid-table that could give me more emotional rollercoaster moments. Aston Villa’s always had a great history."
Meanwhile, William will get his footy fix this weekend as it has been confirmed he will be at Wembley on Sunday for another big match.
He will be there for the women's FA Cup final, which will be contested between Manchester United and Chelsea. And once the game is over, he will be on hand to present the winners with the trophy.
