Thailand's Princess Soamsavali Kitiyakara has been praised by the United Nations for her work to fight HIV.
The princess - who was previously married to King Bhumibol Adulyadej's son Crown Prince Maha Vajiralongkorn before divorcing in 2001 - was feted for her "tireless dedication, commitment and leadership" in the country's HIV response.
UNAIDS Executive Director Michel Sidibe said: "Through deeds, words and provision of resources where they are most needed, Your Royal Highness has shown true vision and commitment on HIV. I look forward to our ongoing collaboration to save and improve lives."
On an official visit to the Suan Kalub Palace in Bangkok he presented Princess Soamsavali with a commemorative plaque for her efforts to prevent mother-to-child transmission of HIV and HIV-related discrimination.
Mr Sidibe noted Princess Soamsavali's longstanding involvement in the HIV response, which dates back 25 years.
He added: "I would like to see Bangkok free of HIV. This means greater action is needed to break down barriers to ensure support is given to those who need it most."