She died on Thursday evening at a hospital in Bangkok. According to a statement released by the Bureau of the Royal Household, she had been unconscious and was being cared for in hospital.
In a televised speech, Prime Minister Anutin Charnvirakul praised the late princess for her “commitment to building a society of kindness, justice and equality will forever remain as a moral legacy for the nation, a guiding light for generations of Thais”.
Anne, 75, will travel east with her husband, Sir Tim Laurence, from July 13 to 17.
During the final two days, Anne hold an audience with the Thai Prime Minister as well as Their Majesties the King and Queen.
The Princess Royal will also pay respects to Her Late Majesty Queen Sirikit, the Queen Mother, who died last year, during the visit.
Princess Anne has previously visited the country in 1972, 1979 and 1987.
Anne’s programme during the visit also aims to reinforce bilateral ties between Britain and both nations, encompassing diplomatic engagements, charitable work and cultural exchanges.
It remains unclear when the Thai Princess’ funeral will take place.