Ranjitsinh Mohite Patil, son of senior Nationalist Congress Party (NCP) leader Vijaysinh Mohite Patil who was himself a former MP of the party, joined the BJP on Wednesday.
The development comes as a massive jolt to the Congress-NCP combine in Maharashtra, where NCP chief Sharad Pawar has already declared that he won't be contesting the general elections.
Ranjitsinh is all set to contest from Madha set as a BJP candidate. His decision to quit the NCP comes days after Sujay Vikhe-Patil, son of Congress leader Radhakrishna Vikhe-Patil, joined the BJP to contest from Ahmednagar seat, in the wake of the Sharad Pawar-led NCP spurning the Vikhe Patil senior's request to leave aside Ahmedanagar Lok Sabha seat for his son.
Vijaysinh had served as a deputy chief minister in the erstwhile Congress-led UPA government.
The Mohite Patil senior said he was "in agreement" with his son's decision.
It is not known immediately whether Vijaysinh will also join the BJP, as is being speculated.
Ranjitsinh, who reportedly held talks with Fadnavis and also with state minister Girish Mahajan before announcing his shift, heaped praises on Prime Minister Narendra Modi and Union minister Nitin Gadkari for "working to solve problems of farmers".
NCP sources said Vijaysinh, one of the five MPs of the party from Maharashtra, is feeling sidelined in the party.
He had requested NCP chief Sharad Pawar to contest from faction-ridden Madha seat.
However, after keeping NCP leaders and workers guessing whether he would enter the Lok Sabha fray from Madha, Pawar, in a U-turn, announced that he was not keen to contest.