Princes William, Harry, pay tribute to mom Princess Diana on her birthday

Prince William and Prince Harry honored recipients of the Diana Award this week on what would have been their late mother Princess Diana’s 61st birthday.

On Friday, the Duke of Cambride and the Duke of Sussex each shared a message on Twitter honoring the 180 young awardees from the U.K. and around the world who have "demonstrated their ability to inspire and mobilise new generations to serve their communities and create long lasting change on a global scale."

"You are part of an inspirational generation of young people who are changing the world through your actions, and I hugely admire your efforts," William wrote in his congratulatory letter to the recipients. "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."

"I believe there's no better way to celebrate her life and work than through recognising incredible people who dedicate so much time and effort to helping those around them," he added.

The award, which was established in Diana's memory, is "the most prestigious accolade a young person aged 9-25 years can receive for their social acion or humanitarian work," according to the Diana Award website. It is also the longest running award for young people.

While honoring this year's recipients, Harry also shared a video message on how his mother's legacy had impacted him and how he continues to lead by her example today.

“My mother instilled in me and in all of us a drive to speak up and fight for a better world," Harry said. “Now as a husband and a parent, my mother's voice is even stronger in my life. All of you have kept 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."

The brothers' announcements come nearly a month after Harry and his wife Meghan, the Duchess of Sussex appeared publicly with Britain’s royal family for Queen Elizabeth II's Platinum Jubilee -- their first appearance with the family since stepping down from their roles as senior working royals.

Earlier this week, a royal source revealed that Prince Charles, Harry and William's father, was "thrilled" to see Harry in June for the Platinum Jubilee.

"[Charles] of course, hasn’t seen his grandson Archie for a bit of time and so it was very, very, very special to have some time with him," the royal source said. "He hadn't met Lili, his granddaughter, and so to meet her was very emotional, a very, very wonderful thing."

ABC News' Zoe Magee contributed to this report.