While a majority of lawmakers - over 100 - showed up at the Poes Garden home of Jayalalithaa to rally behind Ms Sasikala, parliamentarian V Maitreyan has come out in Mr Panneerselvam's support.
Ms Sasikala, a former video store owner who came to the forefront as party chief after three decades in Ms Jayalalithaa's shadow, is expected to speak to the media for the first time today.
The uncertainty over her swearing-in remains with Governor Vidyasagar Rao yet to return to Chennai. "There is no Tamil Nadu plan on his schedule as of now," said sources close to him.
The Governor has been consulting legal experts on whether Ms Sasikala can become Chief Minister at a time an important verdict in a corruption case against her is expected.
Mr Pannerselvam or OPS, Jayalalithaa's most loyal aide and the only party leader she would repeatedly trust as place-holder when she was forced to quit over corruption cases, has overnight turned into a hero for supporters.
Mr Panneerselvam is caretaker chief minister after his resignation was accepted by the Governor. Last night, after meditating at Ms Jayalalithaa's memorial, he dropped the bombshell that he was willing to stay Chief Minister if his party wanted.
Mr Panneerselvam has been sacked as the AIADMK treasurer, but sources say he may not be a lone ranger. Signs of dissent started on Tuesday afternoon when party veteran PH Pandian, co-founder of AIADMK, came out with stunning allegations that Jayalalithaa didn't die of natural causes and Ms Sasikala's conduct should be investigated.
Last night, Mr Maitreyan, a Rajya Sabha member, called on the caretaker Chief Minister and expressed support for him.
Ms Sasikala, who became friends with Jayalalithaa nearly three decades ago and stayed with her, faces a Supreme Court verdict next week on charges that she, along with Jayalalithaa, amassed enormous wealth far exceeding their known sources of income.
After his rebellion, Mr Panneerselvam went on social media for support. Hundreds of supporters were seen dancing outside his house in a huge show of support and social media was flooded with tweets and memes that greeted him as "Thalaiva" or "great leader" - often associated with south mega filmstar Rajinikanth.
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