"Vote of Confidence to be taken on 18th.#TNAssembly," the AIADMK tweeted.
Meanwhile, All India Anna Dravida Munnetra Kazhagam (AIADMK) MLAs head back to Kuvathur's Golden Bay resort after Tamil Nadu cabinet and Palanisamy's oath ceremony.
Tamil Nadu Governor Ch. Vidyasagar Rao earlier in the day appointed AIADMK legislature party leader Palanisamy as the Chief Minister.
"Governor invites AIADMK's legislature party leader Edappadi K.Palanisamy to form government," the AIADMK tweeted.
The Governor has asked Palanisamy to seek vote of confidence in 15 days, the Raj Bhawan said in a statement.
Palanisamy, along with Tamil Nadu ministers Jayakumar, K.A. Sengottaiyan, S. P. Velumani, T. T. Dinakaran and K. P. Anbazhagan met the Governor earlier in the day.
The Governor heard competing pitches last night from within the ruling party of the state over who should be the Chief Minister.
The Governor first met with Palanisamy, who claimed to have the support of 125 legislators.
Next up was Panneerselvam, who claimed to have the support of 11 MLAs.