Even some political parties, as we speak, are undecided with regard to their willingness to support Ubolratana as the prime ministerial candidate.
It is being closely watched as the first chance for Thailand to return to democracy after five years under military rule.
But in practical terms, she today enjoys all, or most, of the same privileges as her siblings - except she is expected to be subservient to her younger brother, the king.
Despite being a a constitutional monarchy since 1932, Thailand's royal family has wielded great influence and commanded the devotion of millions.
"It'll be hard for parties to run against the princess", said Paul Chambers, a lecturer at Naresuan University's College of ASEAN Community Studies in the country's north. "Voters would find it hard to choose someone that's not part of her party, because Thai ideology puts the royals at the top".
"Bringing a high-ranking member of the royal family to politics, in whatever manner, is an act in violation of the royal tradition and national culture and highly inappropriate", the announcement reads.
A Thai princess will run for prime minister in upcoming elections, in a stunning twist that pits the high-profile royal against the chief of the ruling junta who had hoped to maintain his grip on politics.
However, the nomination of a member of the royal family by the pro-Thaksin Thai Raksa Chart party could change that dynamic.
"I would like to say once again that I want to see Thailand moving forward, being admirable and acceptable by worldwide countries, want to see all Thais have rights, a chance, good living, happiness to all", she said, concluding with "#ILoveYou".
Ubolratana is the first-born of four children of the late King Bhumibol Adulyadej and Queen Sirikit, with the current king the second-born. Because she will be seen as a representative of the monarchy - the nation's most revered and respected institution - it will be hard to block her political rise.
The new Constitution written after Prayut seized power included a 250-member Senate appointed by the military that would also be able to vote for the prime minister.
Thai Raksa Chart was created previous year as part of a strategy to diversify the clan's political assets in case its main vehicle, the Puea Thai party, was dissolved by the junta that deposed the government Yingluck helmed from 2011 to 2014. She lost her special royal titles more than four decades ago when she married a commoner, an American, but is still called and widely regarded as a princess.
In an Instagram post today, the princess did not directly mention her brother or her political hopes, but thanked supporters for their "love and kindness toward each other over the past day" and expressed gratitude for their support for her.
Rivalry between the Bangkok-centred, royalist elites and Thaksin and his rural-based supporters has brought street protests, military coups, and violent clashes over nearly 15 years.
The other destabilizing element in Thai politics was the 2001 election as prime minister of telecommunications tycoon Thaksin Shinawatra. In a sign of the extreme sensitivity, three Thailand-based legal and political analysts declined to comment on her candidacy.
Thaksin's nephew, Rupop Shinawatra, is third on Thai Raksa Chart's party list. But she is still regarded in the public mind as a member of the royal family, and her entry into politics sets an unprecedented quandary for her opponents in the March elections.
"I am not aiming to extending my power but I am doing this for the benefit for the country and the people", he said.
The princess has a heavier media presence than any of her siblings, ranging from appearances in Thai movies and television to an Instagram page with about 100,000 followers.
Soon after Friday's announcement, her catchphrase #SongPhraSlender (Long Live Slender) was number one on Twitter in Thailand.
Thailand also has a draconian lese majeste law that punishes defamation of the immediate royal family with up to 15 years in prison. One of her children died in the 2004 Indian Ocean natural disaster and tsunami the day after Christmas that killed hundreds of thousands.
Whether Ubolratana or Thaksin is de facto in charge, the government will face seemingly intractable major issues well beyond energetic political corruption, a substandard education system, infrastructure bulging at the seams and a rural northern area that remains mired in poverty.