John Harkes says his son is among the players to have benefited from Wayne Rooney's natural "coaching instinct" long before the England legend gets to work on the training ground at Derby County.

England's leading all-time goalscorer this week agreed to cut short his spell with DC United and join ambitious Championship side Derby as a player-coach in January.

Rooney has been a big hit in MLS and Harkes revealed that it is not only the former Manchester United striker's class on the field that has made a lasting impression.

The former United States captain recalled how his son, Ian, experienced at first hand Rooney's desire to pass on his skills and experience when they were team-mates at the Washington franchise.

The versatile ex-Derby man told Omnisport: "Wayne Rooney has made a big impact at DC. It's always good to see Wayne from a distance and you can admire his work, but you could tell he already had that coaching trait within him.

"It was present all the time, so players gravitated to him and he was like an extension of the coaching staff already at DC United when he came because of all of his experience and what he sees in the game.

"He was coaching on and off the field. I remember Ian [who now plays for Dundee United] telling me there was one training session where they did a lot of fitness and Ian was a little bit shy in terms of asking him, 'would you mind helping me with my finishing outside the box' as a midfielder breaking through the lines.

"Wayne said 'no, of course I wouldn't'. He picked up some water and a bag of balls, they went over and he was working with my son. It was fantastic to see that attitude and work ethic that he has.

"It passed on not just to the players on the pitch, but in the dressing room and everything else. He's already got that coaching instinct in him and hopefully Derby brings the best out of him as he transitions in January.

"The conversations I had with Wayne when he came to DC United early on, it was clear he was still hungry to win but also to make that transition to becoming a coach. 

"I think he is a fantastic signing for Derby and it looks to be a win-win for both an ambitious club and Wayne.

"Hopefully he focuses on being the best he can as a player, but also realises it's a learning experience for him and it'll be great for him. He's a great player and Derby are getting a guy that still wants to win trophies, so it's great for the club."