BANGKOK (Reuters) - Thailand on Friday detailed plans for the coronation of King Maha Vajiralongkorn, beginning next month with the gathering of holy waters in preparation for three days of ceremonies in May expected to cost about $31.5 million.

Thailand's King Maha Vajiralongkorn attends the annual Royal Ploughing Ceremony in central Bangkok, Thailand, May 14, 2018. REUTERS/Athit Perawongmetha

Thais are invited to wear yellow to show support for the king starting in April and for nearly four months until his birthday in late July, Deputy Prime Minister Wissanu Krea-ngam told reporters.

Vajiralongkorn, also known by the title King Rama X, became constitutional monarch following the death of his revered father, King Bhumibol Adulyadej, in 2016.

The coronation was delayed until after a mourning period for Bhumibol, who was cremated in October 2017 in a grand royal funeral in Bangkok.

“April 6 will mark the beginning of the coronation ceremonies. It is Chakri Day, which fortune tellers say is an auspicious day to collect holy waters,” Wissanu said.

Chakri Day commemorates the 1782 founding of the Chakri Dynasty by King Rama I, whose descendents have since reigned over Thailand.

The official coronation will be a mix of Buddhist religious ceremonies and Hindu Brahmin rituals. The king will be crowned on May 4, followed the next day by a celebration procession. He will meet the public and foreign dignitaries on May 6.

“The king will be showered with holy waters and crowned before noon on May 4,” Wissanu said.

Thailand has been a constitutional monarchy since 1932, but the king is regarded as the spiritual protector of its people and culture.

The coronation will be a first for most Thais, after King Bhumibol reigned for seven decades.

King Bhumibol was revered by Thais and the deep relationship between the monarchy and the military helped facilitate a smooth royal transition following his death.

Since then, Vajiralongkorn has overseen sweeping changes to royal affairs, including the running of palace finances, which were formerly managed by the government.

Wissanu said the military-run government has set aside 1 billion baht for the coronation ceremomies, about one-third the cost of King Bhumibol’s funeral.

The kingdom will hold elections on March 24 meant to restore democracy after a 2014 military coup ousted an elected prime minister, though changes to the constitution in the interim ensure the military will retain a great deal of control.