Chennai: AIADMK Rajya Sabha member N Jothi, who resigned from the party last week after he was ignored for re-nomination by party chief J Jayalalithaa, on Friday evening formally joined the DMK.
Jayalalithaa had chosen N Balaganga to fill the seat for the party.
At a ceremony in Anna Arivalayam, the DMK headquarters, Jothi alleged that he was "repeatedly threatened" by Jayalalithaa.
Jothi, a powerful lawyer and two-time Member of Parliament, last week alleged that Jayalalithaa was completely under the control of her close aide N Sasikala and her relatives.
Jothi on Friday told the media here: "I was repeatedly threatened over the telephone and physically by Jayalalithaa and by Sasikala's relatives."
He quit the AIADMK because of the "unexplained relationship that exists between Sasikala and Jayalalitha" and also "due to the fact that Sasikala controls the entire wealth of Jayalalithaa and the political apparatus".
"It is only a matter of time," Jothi said, "before Jayalalithaa is totally isolated in all respect."
"The only place now I can rightfully belong to is the DMK," he said, "because this is the only organisation that will give me appropriate protection and a political future."
Jothi, a renowned advocate, has been counsel of Jayalalithaa and fellow AIADMK members for as many as 117 corruption cases, in many of which the AIADMK leader has been successfully acquitted.
Jothi hoped that he would "also be of use to the DMK in my legal capacity".
Jayalalithaa has called Jothi's withdrawal from 113 continuing AIADMK cases as "unethical" and accused him of trading information. The DMK too filed a number of cases against Jothi, who may now get relief in them.