"I will work for the cause of uplift of the society till death. So, for the question who after me, the answer is Stalin who is sitting amongst you and you should not forget it," he told his partymen.
The 88-year-old DMK patriarch was addressing party cadre at a function in which over 2000 PMK men joined the DMK. His remarks were welcomed with loud cheers.
Karunanidhi had more than once given enough hints that Stalin is his political heir-apparent, an issue that had led to sibling rivalry with M K Alagiri, the elder son and Union Minister.
But, this is the clearest hint ever, more so after the 2011 electoral debacle which saw a growing clamour for Stalin taking over the party.
Ever since 59-year old Stalin was given prominence in the party and elevated as Deputy Chief Minister in 2009, there have been indications that he will succeed Karunanidhi.
Alagiri had openly resented such hints saying he would not accept anyone else other than his father as leader.
The Madurai strong man, who is two years elder to Stalin, had a couple of months ago made no secret about his unhappiness over selection of party functionaries in his home turf, particularly in the youth wing headed by Stalin.
Alagiri had said his recommendations were neglected by the party leadership, an indirect attack on Stalin.
Noting that the PMK workers have joined the DMK because of shortcomings in that party, Karunanidhi hit out at PMK Chief S Ramadoss, for "unnecessarily" dragging him into controversies.
Ramadoss' recent attempt to bring together leaders of various castes on a common platform to campaign against inter-caste marriages involving Dalits drew sharp reaction from major political parties and Karunanidhi describing it as a "dangerous trend".
