The new father, 35, who arrived to the event hand-in-hand with his wife, Meghan, Duchess of Sussex, grew overcome with emotion as he described the couple attending the event in 2018 as expectant parents.
"Last year when my wife and I attended we knew we were expecting our first child and no one else did at the time, but we did. And I remember ... " Prince Harry shared before pausing to collect himself.
The event's host, Gaby Roslin, then stepped forward to comfort him.
"Sorry," he told the audience before continuing. "I remember squeezing Meghan’s hand so tight during the awards and both of us were wondering what it would be like to be parents one day."
"And more so, what it would be like to do everything we could to protect and help our child should they be born with immediate challenges or become unwell over time," he went on.
Welcoming son Archie last May has given him new insights into the work WellChild does to help seriously ill children in need, the prince said.
"And now, as parents, being here and speaking to all of you, pulls at my heartstrings in a way I could never have understood until I had a child of my own," he shared.
The annual ceremony honors inspirational children dealing with serious illness and the caretakers who help them.
Prince Harry and Meghan, 38, also attended a pre-ceremony reception where they met with several of the night's winners and honorees.
Harry has been a patron of WellChild since 2007. Earlier this year, he and Meghan encouraged followers to donate to WellChild and other charities in light of a grassroots-led global baby shower prior to Archie's arrival.