Brunei's sultan will mark 50 years on the throne with lavish celebrations including a glittering procession, a 21-gun salute and a ceremony at his vast, golden-domed palace.
The festivities for Sultan Hassanal Bolkiah - which will include the monarch being carried past huge crowds of well-wishers in a chariot - are the centrepiece of events to mark his golden jubilee.
The 71 year old, the world's second-longest reigning monarch, ascended to the throne in October, 1967.
His decades ruling one of the world's few absolute monarchies have seen the country gain full independence from Britain and living standards soar to among the highest in the world due to abundant oil and gas reserves.
But the reign of Sultan Hassanal, one of the world's richest men, has also been marked by controversies.
These include the sensational family feud which revealed details of his brother Prince Jefri Bolkiah's jet-set lifestyle.
The jubilee will be a chance for citizens to focus on celebrating the life and times of Hassanal, a father-figure monarch who remains widely revered.
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The festivities will begin with the sultan and his wife inspecting a royal guard of honour, followed by a gun salute.
They will hold an audience at the sultan's palace, a vast complex of resplendent white buildings with golden domes and almost 1,800 rooms, which will be attended by guests including members of the royal family and ministers.
The climax of Thursday's events, which are part of over two weeks of jubilee celebrations, will be a procession through the capital Bandar Seri Begawan.
The sultan and his wife will be pulled on an ornately decorated, gold chariot by 50 of their subjects, with about 80,000 well-wishers expected to line the route.
Marching bands and members of the armed forces and military will also take part in the procession.
South East Asian leaders and Middle Eastern royalty will attend a banquet in Brunei Friday to mark the jubilee.
They include Indonesian president Joko Widodo, Malaysian prime minister Najib Razak, Myanmar leader Aung San Suu Kyi, and Philippine president Rodrigo Duterte, according to organisers.
Bridget Welsh, a South East Asia expert from John Cabot University, said the sultan was using the jubilee celebrations to "re-affirm the nature of the Brunei state, and the personalistic nature of that state around him".
"He's always had a cult of personality around his monarchy," she said.
The sultan only comes behind one sovereign in terms of having the longest reign - Britain's Queen Elizabeth II, who ascended to the throne in 1952.
Brunei, with a population of about 400,000, has been ruled by the same royal family for 600 years.