Former Minister V Mullaivendhan and former MLA Nellai V Karuppasamy Pandian joined the DMK at the party headquarters 'Anna Arivalayam,' here, a party release said.
The duo joining the party comes ahead of a proposed 'silent rally' here on September 5 by expelled DMK leader M K Alagiri, the estranged brother of the party chief.
Their re-admission is perceived as a tactical move to pre-empt any attempt by loyalists of the former Madurai strongman to woo disgruntled DMK leaders.
Alagiri has been making a strong pitch to re-enter the party, from which he was expelled in 2014, since the death of his father M Karunanidhi on August 7 and has accused Stalin of blocking it.
The former union minister, who had maintained all along that he would accept none other than his father as leader, made a climbdown yesterday when he said he was ready to recognise his brother as the party chief.
Mullaivendan, a three-time MLA belonging to Dharmapuri district, was expelled from the party in 2014 following DMK's debacle in the Lok Sabha polls held that year.
When the DMK sought an explanation from him over some charge related to the party's poll performance, he issued a statement against the high command and was expelled later. He was with the DMDK since 2015.
Karuppasamy Pandian, a leader with considerable clout in Tirunelveli, was expelled from the DMK in 2015.
He joined the AIADMK in 2016 the presence of late party supremo J Jayalalithaa and quit the party last year.
Pandian, also a three time MLA, was originally with the AIADMK for decades since its inception. He joined the DMK in 2000 after he was sidelined for some time.
Party sources told PTI that the duo have undertaken to "stand by the party; work for it and abide by the high command's guidance to strengthen the party."