The Sasikala camp on Wednesday nominated TTV Dhinakaran as the AIADMK candidate for the RK Nagar bypoll.
This comes just days after AIADMK announced a "restructuring" of its parliamentary board to select a candidate for the bypoll.
The Sasikala faction said this decision was taken with the consent of jailed AIADMK leader VK Sasikala, who is also Dhinakaran's aunt.
A bypoll was necessitated after the death of former Tamil Nadu chief minister J Jayalalithaa. The bye-election was suspended earlier this year after allegations of voter bribery surfaced.
On October 15, Dinakaran said he is ready to contest bypoll but said party general secretary V K Sasikala would decide the candidate. "The party General Secretary V K Sasikala will select the candidate and announce the name," he said.
Dinakaran, at the moment, is engaged in a bitter tussle with the K Palaniswami-led government. Dinakaran had met the then Governor Ch Vidyasagar Rao and sought removal of Palaniswami as Chief Minister.
In August, 19 MLAs supporting him had met Rao and pressed for a similar demand, saying they had lost confidence in him.