The Congress support had come at the last minute after some backroom pulling and pushing.
During the meeting Kanimozhi thanked the Congress president for supporting her in the Rajya Sabha elections this week. The Congress support has set off speculations that the former allies were coming together again. The Karunanidhi-led party had snapped ties with its nine-year-old ally in March on the Sri Lankan Tamils issue.
Kanimozhi was accompanied by senior party leader and former union minister TR Baalu and she told reporters that "I was here to offer my party's thanks to Sonia Gandhi for supporting us."
Karunanidhi had sent thank you message to Sonia Gandhi on the election day itself. "I would like to thank you and the Congress party on behalf of the DMK and myself for supporting our candidate Kanimozhi in the upcoming Rajya Sabha elections," he had said in a message to Sonia late on Tuesday night.
The DMK chief's daughter had earlier visited the Congress headquarters in Chennai to thank the state Congress chief.
Kanimozhi, an accused in the 2G scam, sailed through the contest by elination process with 31 votes after five Congress' MLAs voted in her favour along with two votes each from two smaller parties - Puthiya Thamizhagam and Manithaneya Munnetrak Katchi. DMK has 23 MLAs in TN House.