Prashant Kishor is the vice president of the Janata Dal United, a key BJP ally.

Delhi Chief Minister Arvind Kejriwal today announced that election strategist Prashant Kishor's consultancy firm I-PAC has come on board with the Aam Aadmi Party (AAP). "Happy to share that @indianpac is coming on-board with us. Welcome aboard!," tweeted Mr Kejriwal. The Chief Minister's announcement comes ahead of the Delhi assembly election next year.

After Punjab results, we acknowledged you as the toughest opponent that we have ever faced. Happy to join forces now with @ArvindKejriwal and @AamAadmiParty. https://t.co/5Rcz4ie6Xs — I-PAC (@IndianPAC) December 14, 2019

Mr Kishor is the vice president of the Janata Dal United, a key BJP ally. However, there have been reports of differences between Bihar Chief Minister and party chief Nitish Kumar and Mr Kishor over the Citizenship Amendment Act.

Mr Kishor, whose wife is Assamese, has been highly critical of the Citizenship Bill, which become an Act after President Ram Nath Kovind gave his assent on Thursday night.

"The majority prevailed in Parliament. Now beyond judiciary, the task of saving the soul of India is on 16 Non-BJP CMs as it is the states who have to operationalise these acts. 3 CMs (Punjab/Kerala/WB) have said NO to CAB and NRC. Time for others to make their stand clear," Mr Kishor had tweeted.

His comments forced Mr Kumar to field two of his party leaders to deliver a sharp rejoinder. "I will not name anyone but if somebody has a problem he is free to leave the party," JD(U) MP Ram Chandra Prasad Singh said today. Another MP, Rajiv Ranjan said if the "party chief has taken a decision then there is no question of going back."

Mr Kishor had joined the JD(U) after he helped Nitish Kumar win the 2015 state elections. Nitish Kumar was then part of The Grand Alliance with Lalu Prasad Yadav's Rashtriya Janata Dal and the Congress. Mr Kishor is expected to meet Bihar Chief Minister and party chief Nitish Kumar in Patna today.

The Indian Political Action Committee (I-PAC) is widely credited for the BJP's "chai par charcha" campaign, which helped the party come to power in 2014 with Narendra Modi as prime ministerial candidate.

The political advocacy group is currently working on the Trinamool Congress' re-election campaign for the 2021 West Bengal Assembly polls. Mr Kishor was brought to Mamata Banerjee's office by her nephew and party lawmaker Abhishek Banerjee on June 6 to help her win a third consecutive term as chief minister amid BJP's resurgence in the state.

The organisation also helped Andhra Pradesh Chief Minister Jagan Mohan Reddy win both state and general elections.

With inputs from agencies