Prince Harry, dressed as Santa Claus, wished a "fantastic Christmas" for the children who lost their parents in the British Armed Forces in a moving video message.
The one-minute clip was aired at the annual Christmas party hosted by Little Soldiers of Scotty, a UK charity providing support to children who lost their parents in military service.
There were 190 people present and the Duke of Sussex jokingly encouraged them to "cause as much chaos as possible humanly!"
He told the children that they are supported and part of "an amazing community".
"I know how incredibly strong you are," he said. "Yes, losing a parent is incredibly difficult, but I know that each of you, helping each other out, will have an incredible future ahead and also have a fantastic Christmas."
Prince Harry could not attend the party in London, but the heartfelt message "meant the world" to the children.
“It can be a tough time of year for these kids, so getting a heartfelt message from Prince Harry really meant the world to them. The message was a surprise and the look on their faces was invaluable, ”said Nikki Scott, founder of Scotty's Little Soldiers, in a press release Friday.
Prince Harry ended his Christmas message by pulling Santa's beard down, smiling, showing two thumbs up and wishing everyone a "fantastic Christmas and happy New Year."
On vacation, Prince Harry, Meghan and baby Archie are "spending family time" in Canada, according to Buckingham Palace.
"They are enjoying sharing the warmth of the Canadian people and the beauty of the landscape with their son," the statement said.