The elder sister of Thailand's King Vajiralongkorn was only 21-years-old when she confirmed her status as the rebel of the family.
In 1972 she renounced her royal titles to marry Peter Jensen, an American she had met while studying mathematics at the prestigious Massachusetts Institute of Technology.
Ubolratana aka Julie Jensen
She lived a comparative commoner's existence in the United States, where she was known as Julie Jensen, for more than a quarter of a century before her marriage broke down.
Return to homeland
Following the divorce, Ubolratana returned to her homeland where she was embraced by her family, treated as a senior royal once more and afforded the wealth and trappings of her re-acquired station.
More accessible image
67-year-old princess has cultivated a more accessible image than her reserved younger brother and shown a knack for reading the sentiments of ordinary Thais.
Embracer of pop culture and spotlight
In an institution that leans heavily on protocol and tradition, she has embraced pop culture and the spotlight.
Last year the princess played the role of a pop star, performing onstage a song popularised by Thai girl group BNK48.
In 2008 she starred in a movie, "Where the Miracle Happens", which opened in Cannes, and played a journalist in her second film foray.
Victim of first hand tragedy
She also experienced first hand tragedy of the huge 2004 Asian tsunami —her autistic son Poom was one of more than 5,000 people killed by the waves in Thailand.
Boldest move to enter politics
Marrying American, singing pop songs on talent shows, roles in movies and posts on Instagram, Princess Ubolratana has long broken the mold of Thailand's royal family but her entry into politics is her boldest move yet.
Rumours turn into reality
Her latest Instagram post on Thursday set tongues wagging as rumours swirled that she had agreed to stand as a prime ministerial candidate for a Thaksin-linked party at the upcoming general election in March.
In a country where people are adept at reading subtle political cues, the signal was clear: the Shinawatras' heartland is Thailand's north and their political colours are red.