The Duke of Sussex has said he is "taking a leap of faith" in stepping back from his life as a member of the Royal Family but said, "there really was no other option".
Speaking at an event on Sunday evening, he said he wanted to make it clear he and Meghan were "not walking away".
"The UK is my home and a place that I love, that will never change," he said.
It is the first time the duke has spoken since it was announced the couple would give up their HRH titles.
Earlier this month, Prince Harry and Meghan said they intended "to step back as 'senior' members of the Royal Family and work to become financially independent".
Beginning his speech at a fund-raising reception in central London for Sentebale, the charity he co-founded which helps children living with HIV in southern Africa, he said: "I can only imagine what you may have heard and perhaps read over the past few weeks.
"So I want you to hear the truth from me as much as I can share, not as a prince or a duke but as Harry."
During his address, the prince said he would always have "the utmost respect for my grandmother, my commander in chief".
"Our hope was to continue serving the Queen, the Commonwealth, and my military associations, but without public funding. Unfortunately, that wasn't possible," he said.
"I've accepted this, knowing that it doesn't change who I am or how committed I am."
As part of a deal finalised on Saturday between the Queen, senior royals, and the couple, Harry and Meghan agreed they will no longer formally represent the monarch.
From the spring, they will stop using their HRH titles and withdraw from royal duties, including official military appointments.
However, the statement by Buckingham Palace said they would continue to maintain their private patronages and associations.
In the speech, posted on the couple's Instagram account, the prince said that when he and Meghan were married "we were excited, we were hopeful, and we were here to serve".
"For those reasons, it brings me great sadness that it has come to this.
"The decision that I have made for my wife and I to step back is not one I made lightly," he said.
"It was so many months of talks after so many years of challenges and I know I haven't always got it right, but as far as this goes there really was no other option."