King George Tupou V of Tonga died Sunday at a Hong Kong hospital aged 63.
Tongan Prime Minister Lord Siale'ataonga Tu'ivakano said in a brief radio address Monday that the king had died at 3pm. Sunday during a visit to Hong Kong.
The premier didn't give a cause of death, but said further details and funeral plans would be released when available.
He also said the king's younger brother and heir to the throne, Crown Prince Tupouto'a Lavaka, was at the king's side when he died.
The monocle-wearing king, who had a penchant for military uniforms and drove around in a London taxi, never married, though he did have a daughter born out of wedlock.
He had a kidney removed last year and suffered other health problems, according to Tongan media reports.
He had reigned over the island nation of 106,000 since his father, King Taufa'ahau Tupou IV, died in 2006.