Appearing in one of several videos, Harry - who served as a host of the ceremony - made reference to how much Diana's voice is still in his life, particularly now that he has become a husband to Meghan Markle and a parent to their two children, Archie, three, and Lilibet, one.
"This is a special year," Harry said in one clip shared on Instagram. "And one where I hope we take extra time, to not just remember how she lived, but to reflect on the life she continues to lead through so many, including the young changemakers with us today.
WATCH: Prince Harry makes touching reference to his children on Princess Diana's birthday
"My mother instilled in me, and in all of us, a drive to speak up and fight for a better world. And now as a husband and a parent, my mother's voice is even stronger in my life.
"All of you have helped keep her voice alive by showing the world how each small action counts, how kindness is still valued, and how our world can be better if we choose to make it so."
Harry and Meghan share two children
The Diana Award takes place annually on the late Princess' birthday. It was established in 1999 in memory of Diana, Princess of Wales and her belief that young people have the power to change the world.
The charity, which runs anti-bullying and mentoring programmes, also rewards young people who carry out inspiring work. Each year, thousands of young people are nominated by individuals and their communities to highlight these selfless acts.
The Duke said his mother's voice is still present in his life
Prince William also shared an important message in honour of The Diana Award on Friday, releasing a statement that read in part: "Congratulations on receiving The Diana Award today! You are part of an inspirational generation of young people who are changing the world through your actions, and I hugely admire your efforts. Your stories are remarkable.
"Many of you face huge challenges in the face of difficult times, yet you are tirelessly breaking down barriers to create a better future for us all. Thank you for your compassion, bravery and absolute determination. You truly are the personification of my mother's legacy and I know she would be so proud of you all."
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