At the auspicious time of 10:09 am the public will be given a rare window into the cloistered halls of Thai power as the key rituals of the three-day coronation begin.

King Vajiralongkorn is known as Rama X of the Chakri dynasty, which has reigned since 1782.

Saturday's ceremony will begin with sacred water from across Thailand anointing the white-robed king inside the Grand Palace.

Hindu Brahmins and Buddhist monks will attend the ceremony which symbolises Rama X's transformation from a human to divine figure.

Then he will take his seat under the nine-tiered umbrella of state where he will be handed the Great Crown of Victory, a tiered gold 7.3 kilogram headpiece topped by a diamond from India.

For most Thais it will be the first time they have witnessed a coronation -- the last was in 1950 for the king's beloved father Bhumibol Adulyadej.

"I'm excited about the coronation. I'm happy to have a king as a pillar of the country," said Chomphu Phueakbamrung, 51, who had waited for hours in the baking sun on Friday to see the king's convoy.

Bhumibol was seen as a figure of unity in politically chaotic kingdom until his death in October 2016.

His son Vajiralongkorn, 66, is less well-known to the Thai public.

Fiercely private and four times married, he has inherited one of the world's richest monarchies and a kingdom submerged by political crisis.

Mystery man

Thailand has been run by an arch-royalist junta since 2014.

Rama X is widely seen as an adroit player of Thailand's treacherous politics, intervening several times -- including just before polls opened for a March 24 election -- during his short reign.

Late Friday he arrived at a hall in the Grand Palace in his favoured cream Rolls-Royce along with his new wife -- now Queen Suthida -- a former air hostess turned royal bodyguard.

Their marriage was unexpectedly announced on Wednesday.

Inside, he warmly greeted family members including his 14-year-old son from his third marriage -- Prince Dipangkorn - and his elder sister Ubolratana.

She stunned Thailand in February when her name was forwarded as a candidate for premier by an anti-junta party -- a move swiftly shot down by her brother the king in a rare royal command.

Harsh lese-majeste laws mean unguarded discussion about the monarchy inside Thailand is virtually impossible.

Thailand's normally hyperactive social media has been subdued in the days leading up to the coronation.

But enthusiasm bubbled on the streets around the Grand Palace where hundreds bedded down for the night on Friday to get a prime spot for the weekend's royal event.

Born on July 28, 1952, the British-schooled Vajiralongkorn is known for his love of cycling and piloting jets, but he spends much of his time overseas -- mainly in Germany -- and remains something of a mystery to many Thais.

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