Delhi Congress President Ajay Maken, addressing a press conference accompanied by Jha, announced that she has joined the party.
"She has come with her friends from AAP. And we have given her a new responsibility in Congress," Maken said.
"And we want to assure her that we will keep on raising the issue of Poorvanchal and Mithilanchal," the Congress leader said.
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"We hope she will become the voice of Poorvanchal and Mithilanchal in Congress," Maken said.
Jha in November quit the Bharatiya Janata Party (BJP) and joined AAP.
She had served as BJP's spokesperson for long and was also the Vice President of the Delhi unit of the party.
Her husband, who represents Darbhanga constituency in Bihar, was suspended from BJP in 2015 after he publicly targetted Finance Minister Arun Jaitley over alleged corruption in the Delhi District Cricket Association (DDCA).