Rugby fan Prince Harry joked he was already "past it" as he helped coach a session for youngsters at Twickenham Stadium today.
The 29-year-old took part in training with schoolchildren alongside former England star Jason Robinson, who threw down the gauntlet to the prince.
"I'll be looking to see what you've got," the World Cup winner said.
But Harry replied: "I think I'm a bit past it already."
The royal is patron of the Rugby Football Union (RFU) All Schools Programme, a project to help boost participation in state schools.
Harry, who is often seen cheering England on from the sidelines, put some of his passing, kicking and tackling skills to the test on Twickenham's famous turf.
Robinson, 39, said: "It's just fantastic to see him out here with the kids.
"He's dripping with sweat. He's put everything into this, because he is passionate about the game."
Robinson joked with Harry that he could make it into the England squad for the forthcoming World Cup in 2015.
"We're looking for a winger or a full-back," he said to Harry.
The famous winger, from Leeds, also gave the fourth-in-line to the throne a pair of his boots.
He told him: "I can't guarantee they'll get you into the England team, but you'll be quick."
After the coaching session, Robinson joked: "We're always looking, if any of the England players go down, we've got a replacement.
"I'm not sure what he's like in contact though, although saying that, it was supposed to be a bit of tagging and he was getting bit rough with me."
Harry wore a white T-shirt and blue England tracksuit bottoms as he ran around the pitch for about an hour.
Red-faced and out of breath, the prince laughed with former England captain Robinson as they tried to out-fox each other.
Harry, who took official RFU coaching qualifications on his gap year, helped coach state secondary school boys and girls from Kelvin Hall School in Hull, Oakbank School in Keighley, West Yorkshire, Oxclose Community Academy in Tyne and Wear, Rokeby School in Newham, east London, and Stonehill High School in Leicester.