NCP leader Bhaskar Jadhav joined the Shiv Sena in the presence of party chief Uddhav Thackeray after resigning from the Maharashtra Assembly on Friday morning.
Jadhav, who represented Guhagar constituency, was part of the Sena before joining the NCP in 2004.
Speaking at Jadhav's induction function, Thackeray said the Sena-BJP alliance talks for the upcoming state Assembly polls were in the final stages.
"The list of seats given by the BJP will be discussed by our party leaders," Thackeray said.