A day after breaking the deadlock, DMK and Congress on Wednesday formalised their seat-sharing pact for the April 13 assembly polls, under which the national party will contest 63 seats.
DMK chief M Karunanidhi and TNCC president K V Thangkabalu signed the agreement, hammered out after hard bargaining by both sides for about a fortnight.
"Following discussions, it has been decided to share 63 seats with Congress," the copy of the agreement released to the media said.
Later, Thangkabalu described the DMK-Congress combine as a "winning alliance."
The seat-sharing talks had run into rough weather with DMK refusing to allot 63 seats and Congress dead set on its demand, which had brought the seven-year-old alliance under serious strain.
The stalemate continued till Tuesday when DMK finally relented to Congress's demand for 63 seats.
DMK and Congress had contested the 2004 and 2009 Lok Sabha polls from the same platform besides the 2006 Assembly elections.
Thangkabalu also said that the election panels of the two parties, comprising Union Ministers P Chidambaram and G K Vasan and Tamil Nadu Deputy Chief Minister M K Stalin on either sides, would meet tomorrow to finalise the constituencies they will contest from.
"We will take good decisions," he said.