"Today, in the presence of national general secretary Abhishek Banerjee and RS MP Derek O'Brien, former Union Minister and sitting MP Babul Supriyo joined the Trinamool family," the party said in a tweet.
In a press conference, after joining the party, Babul Supriyo said that West Bengal Mamata Banerjee has given him a great opportunity and that he is proud of changing his decision of quitting politics.
"I meant it from my heart when I said I'll leave politics. However, I felt there was a huge opportunity that was entrusted upon me (on joining TMC). All my friends said my decision to leave politics was wrong and emotional," he said in a press conference.
"I'm very proud that I am changing my decision. I am coming back for a great opportunity to serve Bengal. I am very excited. I will meet Didi (CM Mamata Banerjee) on Monday. I am overwhelmed by the warm welcome," he added.
In July, Supriyo had announced that he was quitting politics but was later persuaded against resigning as a Lok Sabha member even as he insisted that he would no longer be part of active politics. After meeting BJP president J P Nadda, he told the reporters that he would continue to discharge his responsibilities as a parliamentarian but would withdraw from politics and leave his official residence in New Delhi.
The singer-turned-politician contested the recent Assembly elections in West Bengal from the Tollygunj constituency, losing to TMC's Aroob Biswas.
Following TMC's return to power, Supriyo called Mamata Banerjee a "cruel lady".
"Because I think people of Bengal made a historic mistake by not giving Bharatiya Janata party a chance and by electing this Corrupt, Incapable, Dishonest government & a cruel lady back to power," he said in a now-deleted Facebook post.