Six message books have been arranged at the Centennial Pavilion in the hospital compound. A separate book for VIP guests has been set up at a special desk.

Well-wishers are advised not to gather on the ground floor of the Chalerm Phra Kiart building - where HM the King will stay briefly to recover after the surgery - as the area is used to transport patients and medical supplies.

Outside Bangkok, messages can be signed at all provincial halls and district offices across the country. Bangkok residents can do the same at all 50 district offices in the capital.

During the King's stay, police security will be provided at the hospital and adjacent areas, including the section of the Chao Phya River that borders the hospital.

Special operations officers will man the Chalerm Phra Kiart building, while personnel from the Royal Thai Aide-de-Camp Department will watch the unspecified floor where the King will stay.