Ubolratana Rajakanya, full name Ubol Ratana Rajakanya Sirivadhana Barnavadi, was born in Lausanne, Switzerland. She is a member of the Thai royal family and the eldest child of King Bhumibol Adulyadej and Queen Sirikit and elder sister of King Vajiralongkorn.

She attended primary to secondary levels at Chitralada School. She went to the United States for her tertiary education. She studied at Massachusetts Institute of Technology, graduating with a Bachelor of Science in mathematics in 1973. She later obtained a master's degree in public health at the University of California, Los Angeles.

In 1972, she married American citizen Peter Ladd Jensen and settled in the United States, losing her royal title in the process. 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.

About her career in Entertenming Industry, in 2003 Ubol Ratana starred in a Thai soap opera, 'Kasattiya'. She had a role in Anantalai (2006), a drama series she wrote under the pen name "Ploykampetch". In 2011, the princess and her daughter, Ploypailin Jensen, starred in Dao Long Fah, Pupha Si-ngen.

Ubol Ratana acted in the Thai movie' Where The Miracle Happens', released on 7 August 2008 (in this film she also participated as a screenwriter). She plays a "lonely-at-the-top" CEO who begins a life of philanthropy after the death of her only daughter. In 2010, she appeared in the action film 'My Best Bodyguard', released on 21 October 2010 and in the romantic film 'Together' (2012).

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 an emergency royal decree 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. Edit Biography