The Duke of Sussex joked with one of his Sandhurst instructors, telling him she used to yell at him “so much”.
Harry surprised Invictus Games Team UK competitors with a video call as the members gathered for a final training camp before the event takes place in the Netherlands later this month.
The Duke founded the games to help rehabilitate injured or ill service members and veterans around the world, challenging them to compete in sporting events similar to the Paralympic Games.
After being delayed by the pandemic, the next edition of the international competition will take place in The Hague from April 16-22.
The room burst into laughter when Harry commented that the competitors had had two years to prepare for the games and therefore fitness should not be an issue.
“You realize that nobody, not just you, nobody has an excuse not to be in good shape now,” he joked.
Harry also inquired about former Royal Army Physical Training Corps instructor Vic Wales, who was on the teaching staff when he was a cadet at Sandhurst.
“Is my PTI from Sandhurst here somewhere?” Harry asked, before spotting her and exclaiming, “Here she is.”
He said: “I can’t believe after how many years, 15 years, our paths are about to cross again.
“You were yelling at me so much.”
Harry seemed to be told he needed it, as he then said, “I needed it. Yeah cool. It’s also pretty fair.
Ms Wales, 44, from Newcastle, competes in five events: rowing, cycling, archery, powerlifting and athletics.
She broke her back in a training accident 11 years ago and was discharged on medical grounds.
Giving a team talk to the competitors, Harry said: “For a lot of you already, as far as I’m concerned, you’ve already won gold just by getting to this point.
“The fact that you’re sitting there now wearing this band and being able to wear the Union Jack on your arm again means so much to each and every one of you.”
Britain’s team captain Rachel Williamson, a 33-year-old RAF veteran from Rutland, Leicestershire, told Harry on the call, which took place on Saturday: “It’s been a very long journey for get here, but what an incredible team to do it with.
“We’ve been through some ups and downs with the pandemic, and I know as soon as we all get there, it’s going to be just amazing to just watch the team and see how far we’ve actually come. It will be really special.
Afterwards, she said: “The call was such a surprise, but it was amazing to see Prince Harry again.
“I absolutely loved it, it was like talking to another member of the Invictus family.
“He just says the right things. The main thing he said was “yes, you lost your uniform, but now you can wear this brand new uniform again” and it touches us all so deeply.
“We know he understands where we come from and where we come from.”
Former RAF Corporal Kelly Leonard, vice-captain of the British team, 44, from near Shrewsbury, Shropshire, said after the call: ‘I was almost in tears when he spoke to us as a team . It was really exciting.
“The message was about what Invictus is, this resilience and this journey. It was really wonderful to see him.
Charity Help For Heroes is responsible for the selection, training and welfare of UK competitors.
Last weekend, friends and family of the British team cheered on them from behind the scenes at training camp, supported by the Royal British Legion.
The British team will compete in nine sports: athletics, archery, wheelchair basketball, cycling, powerlifting, indoor rowing, wheelchair rugby, swimming and sitting volleyball.
Harry was instrumental in bringing the games to the UK in 2014, when 300 competitors from 13 countries took part in the inaugural competition in London.
A trip to the Warrior Games in Colorado a year earlier had been the inspiration, as Harry had seen firsthand how the sport helped inspire recovery and support the rehabilitation of injured troops.