190501 King Maha Vajiralongkorn
People walk past a portrait of Thailand's King Maha Vajiralongkorn in Bangkok on May 1, 2019, ahead of his coronation which will take place from May 4 to 6 Image Credit: AFP

Bangkok: Thailand announced on Wednesday that King Maha Vajiralongkorn's long-time consort had become his fourth wife, bestowed with the title Queen Suthida - a surprise move just days before his coronation.

The Royal Gazette published an announcement saying Suthida Vajiralongkorn na Ayudhya, a former flight attendant, had "legally married" the king in accordance with royal traditions.

"Therefore, he bestows (the title) on General Suthida Vajiralongkorn na Ayudhya from Queen Consort to Queen Suthida as of now," the announcement said.

The unpredictable monarch is due to be crowned the 10th monarch of the Chakri dynasty in an elaborate three-day ceremony starting Saturday.

Long seen trailing the king in public events as part of his personal security retinue, Suthida, a former Thai Airways flight attendant, was given the rank of "general" in 2017.

Vajiralongkorn, who has been married three times, has spent much of his time in Germany.

Harsh lese-majeste laws have shielded public scrutiny of his colourful private life, and all media in Thailand must self-censor.

This weekend's coronation will be the first since Vajiralongkorn's late father's nearly 70 years ago.

It was not immediately clear what role Queen Suthida will play in the ceremony.