"Metro Man" E Sreedharan formally joined the Bharatiya Janata Party on Thursday, party leaders said.
Sreedharan joined the saffron party at a meeting organised at Changaramkulam as the "Vijay Yatra" led by Kerala BJP chief K Surendran reached there on Thursday night, party leaders said.
Surendran welcomed Sreedharan with a garland in the presence of a large number of Bharatiya Janata Party workers.
Addressing the meeting, Sreedharan said it is one of the greatest moments in his life.
The 88-year-old technocrat also thanked Surendran for giving him an opportunity to work for the BJP.
Sreedharan, popularly known as the "Metro Man", had announced his decision to join the saffron party last week.
He has also said he will contest the Kerala assembly polls, likely to be held in April-May.