Padmaja Venugopal, daughter of former Kerala Chief Minister K Karunakaran, has joined the BJP.
She received her party membership from BJP's national leader and Union Minister Prakash Javadekar in New Delhi on Thursday.
Padmaja had been in denial since the news of her imminent switch to the rival party became public a few days ago. With her switch complete, the children of two stalwarts in the Congress party in Kerala, have joined the BJP.
Former Kerala Chief Minister A K Antony's son Anil Antony had abandoned the Congress party and joined the BJP last April. He will contest the upcoming Lok Sabha polls from the Pathanamthitta constituency as a BJP candidate.
Karunakaran, who died in 2010, was a doyen of the Congress party in Kerala. He was a four-time chief minister of Kerala.
Padmaja said she was unhappy with the Congress party and credited the influence of Prime Minister Narendra Modi behind her decision.
"Modiji is a very strong leader and that is the only reason I came to this party," Padmaja said.
"I was not happy with Congress party for so many years, especially since the last Assembly Election. I complained with the High Command but there was no response. I came to see the leadership two or three times, they didn't give me an appointment.
"I want to work peacefully. Each party should have a strong leadership. In the Congress party there is no leadership. I have great respect for madam Soniaji, but I couldn't see her. That is why I took this decision.
Will she contest?
Padmaja was asked if she will contest for the BJP in the upcoming Lok Sabha polls. The BJP had earlier declared its candidates to 12 Lok Sabha seats in Kerala. "No one has asked me to contest, yet. And I haven't asked either," she told media persons in Delhi.
Javadekar, who is the prabhari (in charge) of BJP in Kerala, said during the event that "she will be a good campaigner". Padmaja will be in Thiruvananthapuram on Friday and it is understood that she would campaign for Rajeev Chandrasekhar in the state capital, where he is contesting against sitting MP Shashi Tharoor.
Javadekar, who claimed that Padmaja joining the BJP will result in a 'big churning in Kerala', added: "In our party we give everybody respect, responsibility and role. That is what we are going to offer everybody."