The Duke of Sussex has co-hosted a virtual event paying tribute to injured US military service personnel and veterans.
Prince Harry, who served 10 years in the Army, appeared alongside US First Lady Jill Biden, Secretary of Defence Lloyd Austin and Ken Fisher, CEO of military charity, Fisher House Foundation.
All were due to attend the 2021 Warrior Games in Orlando, Florida, which were cancelled due to coronavirus-related concerns.
The Warrior Games is a multi-sport event for wounded, injured or ill service personnel and veterans organised by the US Department of Defence, which has taken place annually since 2010.
Speaking from his home in Montecito, California, the Duke said the Warrior Games were the inspiration behind the Invictus Games, first held in London in 2014.
He said: "I am so sorry that we're not all together at the Warrior Games where we should be.
"The pandemic has certainly changed or flipped life upside down for so many people.
"I will never forget that first visit that I had to the Warrior Games, which inspired me to create the Invictus Games and the Invictus Games never would have been created had I not been inspired by every single one of you, and your companions, and the families for everything that you give to the service of this country."
Harry was inspired to found the Invictus Games after attending the Warrior Games in Colorado in 2013 and seeing how injured American military personnel thrived on the challenge of taking part in competitive sports that aided their recovery.
Watch: Prince Harry on how Invictus Games have 'changed how we view disability'.
He said: "It's not about the medals. It's not even so much about the winning, as far as most of us are concerned you guys have already won.
"These games are so important, whether it's the Warrior Games, whether it's the Invictus Games, it is ultimately the reminder of service, both at home and overseas.
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"It is about caring for our physical as well as our mental fitness.
"And that, again, is not just those who wear the uniform, but every single one of you. Because as we know, once served, always serving and that goes across the whole family network."
Speaking at the start of the event, Dr Biden said: "Twenty years ago our world broke apart and the shockwaves of 9/11 continue today but, as the President and I visited the September 11 memorials this weekend, I was reminded of the humanity that shined through the inhumanity of that day.
"There was a call to defend the values we hold dear as we waged a global war on terror and a courageous group of men and women stepped forward to say 'Me, I will go'.
"And that includes you, Harry, you live by a simple principle – serve together, recover together."