Princess Ubolratana Rajaka of Thailand attends "Thailand Hub of Entertainment", a film and entertainment industry event for investors, in Hong Kong.
Princess Ubolratan did not comment on her prime ministerial candidacy, but thanked her supporters and said she wants Thailand to be "moving forward".
Hours later, a royal command from the king appeared to put a pin in her unprecedented political aspirations.
Uncertainty and conjecture have coursed through Thailand since Friday when the Thai Raksa Chart party made the explosive announcement of Princess Ubolratana, King Maha Vajiralongkorn's elder sister, as their candidate for premier after the March 24 election.
The vote, set for March 24, will be Thailand's first democratic elections since ex-Prime Minister Yingluck Shinawatra, who is also Mr Thaksin's younger sister, was ousted five years ago.
In a world of strict decorum that defines Thai royal life, she stands out for her accessibility - she is an actress and singer, and replies to queries from the more than 97,000 followers of her Instagram account.
She gave up her royal titles after marrying an American and she has starred in soap operas and an action movie.
Thailand's Election Commission is to meet today to consider the candidacy of Princess Ubolratana Rajakanya Sirivadhana Barnavadi, 67, who stunned the nation last Friday when she said she would be the prime ministerial candidate for a populist party loyal to the ousted Thaksin Shinawatra.
After unusually blunt criticism from King Vajiralongkorn, the Thai Raksa Chart party had no choice but to accept his instruction that members of the royal family could not be brought into politics. The commission is likely to follow the wishes of the monarch, who holds a semi-divine place in Thai society.
"The EC must therefore take steps to dissolve the party", Paiboon said, citing Section 92 of the 2018 Political Party Act's stipulation on dissolution of the party when it has obtained credible evidence that it has committed an act deemed hostile to constitutional monarchy rule. His alleged involvement rattled royalists who see their campaign against Thaksin as a way to protect the monarchy. Prayuth was the Thai army chief in 2014 and led the coup that overthrew a government led by Thaksin's sister.
Parties loyal to former telecommunications tycoon Thaksin have defeated pro-establishment parties to win every election since 2001, but since 2006 each of their governments have been removed by court rulings or coups.
Her shock nomination broke with a long-standing tradition of members of the royal family staying out of politics.
The Thai Raksa Party is aligned with the country's exiled former leader, Thaksin Shinawatra.