With the 63-year-old lying in a casket in the throne room of his palace, which like most in Tonga has been swathed in black and purple fabric to note his death, his devoutly Christian people prayed and sang outside.
Dressed in black and wearing the traditional woven ta'ovala mats around their waists, men and women and children in school uniforms gathered outside to mark the eccentric royal's passing from just before sunset on Monday.
"It's a major event that affects all Tongans," said Sandra Fifita, acting director of the Ministry of Tourism, wiping away tears.
"He is our king and we have such respect for him as our king and our leader."
As the sun went down Monday, the lighting of small fires around the palace walls began, continuing an old tradition of keeping the grounds lit during the lying in state of a monarch.
From then through to dawn, religious groups were led into the palace grounds to sing hymns and join in prayers led by the royal chaplain for the late monarch credited with bringing democracy to the small and poor Pacific nation.
The funeral for the king, who will be succeeded by his younger brother King Tupou VI, will be an elaborate ceremony in which Tongans will strictly observe protocol.
Those attending are expected to wear black clothing, including ankle length skirts for women and the knee-length cloth-wrap skirts for men, both sexes wearing a ta'ovala, many with a pandanus leaf skirt over the top.
The king, who died in Hong Kong over a week ago, arrived back in Tonga on a Chinese chartered flight on Monday. The cause of his death has not been released but he underwent an operation last year for cancer.
Close to 150 foreign dignitaries are expected to attend the funeral for a man United States President Barack Obama described as a visionary leader dedicated to democratisation.
One of the dignitaries present at the funeral includes Australian Governor-General Quentin Bryce, who is attending ahead of a 10-day tour of the Pacific.
