"I am starting a new journey in my life today, I plan to embark on my political journey at an appropriate time," said Ms Jayakumar, addressing her first press conference on a day the ruling AIADMK marks the birth centenary of its founder and Jayalalithaa's mentor, MG Ramachandran or MGR. She did not rule out contesting from her aunt's RK Nagar constituency.
She also took digs at Jayalalithaa's close friend Sasikala Natarajan, elected by the AIADMK as their new boss weeks after the Chief Minister's death on December 5.
"I cannot accept anyone else in Jayalalithaa's position," declared the 42-year-old journalist who bears a striking resemblance to former Chief Minister. She insisted that most of the cadre "want me as leader".
But whether she will join the AIADMK and openly challenge Sasikala or start her own party is a decision she says she will take "after consulting with the party cadre and the people".
A section in the party has projected her as the counterweight to Sasikala Natarajan, who has emerged as Jayalalithaa's all-powerful replacement after decades in the shadows.
"As a blood relative, I wanted to be with her in her most trying times as she was the person I loved the most and I always wanted to be with. I was even looked upon by many as heir apparent to my aunt," she wrote in a blog on NDTV.
There was friction within the family over Jayalalithaa adopting Sasikala's nephew. After the Chief Minister's brother died, all communication stopped.
Over the last few weeks, the crowd of AIADMK workers has been growing slowly but steadily at Ms Jayakumar's Chennai home.
That is not, however, the approved party stand. "Where was Deepa all these years? The party has formally chosen Sasikala as the leader and the real cadre is with Chinnamma," said AIADMK spokesperson CR Saraswathi.