The brother and sister were instructed to go into the living room and open the present the elf from the 'Elf on the Shelf' tradition had left for them.
After initially questioning how a small elf would be able to carry such a large present, the children unwrap it and squeal with delight to find their dad.
The children's dad had been away for three months
"You've missed him haven't you. Three months," said the children's mum who was filming their reaction.
"Daddy's coming back from the navy for Christmas for you."
Watch the video above to see the heartwarming moment in full.
Now if that isn't the best Christmas present of all time, we don't know what is.