Ubolratana Rajakanya

Ubol Ratana Rajakanya (Thai: อุบลรัตนราชกัญญา, RTGS: Ubonrat, pronounced [ʔùʔ.bōn.rát]; born 5 April 1951) is a member of the Thai royal family. She is the eldest child of King Bhumibol Adulyadej and Queen Sirikit and elder sister of King Vajiralongkorn.

In 1972, she married American citizen Peter Ladd Jensen and settled in the United States, after give up her royal title. The couple divorced in 1998, whereupon she resumed her royal duties and position within the Thai court. She is styled in English as Princess Ubol Ratana, without the style Her Royal Highness.

In 2001, she permanently returned to Thailand after a series of visits in the years following her divorce. Almost immediately, she began to fulfill her royal duties by taking part in many ceremonies. She started many charitable foundations that focused on improving the quality of life for the disadvantaged.

In February 2019, in an "unprecedented" move, Ubol Ratana announced her candidacy for Prime Minister of Thailand in the 2019 general election, running as a candidate of the Thai Raksa Chart Party. Later that same day, her younger brother King Vajiralongkorn issued a statement, stating that her candidacy is "inappropriate" and "unconstitutional". Thailand's election commission then disqualified her from running for prime minister, formally putting an end to her candidacy.