The Tupou College boys’ choir sang a comedy riff complete with flying actions and buzzing noises to welcome the couple to its on-site forest, which had Meghan somewhat amused as she peeled into laughter as they sang.
Harry and Meghan were there to dedicate two of the school’s rainforest tracts to the Queen’s Commonwealth Canopy.
The aim of the song was to frighten off any mosquitoes that may have been flying around.
Tonga is rated as a moderate risk for the Zika virus, which can be contracted through mosquito bites. The Foreign and Commonwealth Office advises pregnant women to consider postponing non-essential travel to such countries.
The original plan was for the duke and duchess to walk through the Tuloa forest together, but in the end only Harry did.
Earlier, the royal couple had donned floral garlands and traditional Tongan dress as they were welcomed to an exhibition of Tongan youth projects and handicrafts.
Harry and Meghan had powerful-smelling flowers tied around their necks and were given a ta’ovala – a woven mat wrapped around the waist – which signifies Tongan respect to the higher ranks.
The couple, who arrived in Tonga from Fiji on Thursday, joined Princess Angelika and Prince Ata, King Tupou VI’s son and daughter, at the Fa’onelua Centre, which showcased products including traditional mats and “tapa” cloth, carvings, bracelets made from whale bone and wood.
Inside, they sat on two throne-like chairs in the centre of the room while Princess Angelika delivered a short address after prayer was read.
The princess said the royal couple were “an inspiration to the youth of the Commonwealth” for “shining a light on youth empowerment”, adding that their historic visit to what Captain James Cook called Friendly Islands had inspired the youth in Tonga to be “the best they can be”.
She said the “historical highlight” in relations between Britain and Tonga had been the Queen’s visit to the island in 1953.
She added: “Your visit today draws attention to the fundamentals of today’s youth, youth leadership, youth empowerment and addressing the social, economic and environmental challenges of our region.
“Your visits inspires and has been an inspiration for the youth of Tonga to be the best they can be.
“You are a beacon of hope to us all.”
Harry and Meghan went on to meet local Tongan traders and craftsmen as the Masani group of singers and dancers performed island music and songs.
The duke appeared to do a little jig as the music started.
The couple were given a picture of the Royal Tongan Motif, Fata O Tu’i Tongan.
Artisan Uili Lousi said: “They said they will put it in their home.”
The royal couple started their day with a meeting with the Tongan prime minister ʻAkilisi Pohiva and his cabinet.
They were met by more than 50 civil servants wearing red and black shirts and traditional outfits as they entered the St George Government Buildings.
One child held a sign saying “free hugs”, which Meghan spotted and smiled at.
The duke and duchess will now fly back to Sydney and attend the Australian Geographic Society Awards at the Shangri-La Hotel on Friday evening.