The students at Flakefleet Primary School even had bachelor and bachelorette parties.
Friday's event was designed to teach children about being "proud to be British," school officials said.
Donations poured in, including dresses, crowns, bunting and flowers.
Head teacher Dave McPartlin said the gala was also about "creating memories for the children."
"We did a couple of videos with some of the children acting as Harry and Meghan and put them on social media and we were just inundated with people offering their services," he said. “It’s been quite overwhelming and humbling. People have been knocking on the door with donations."
Hundreds of residents turned out to wave and cheer the "little prince" and his mini-Meghan.
"When they walk to that church and the streets are lined and everybody is waving at them, they are going to feel like royalty," he said.