The 37-year-old "Dirty Picture" actress joined the micro-blogging site six years ago but made it official only now after many fake accounts in her name surfaced.
Filmmaker Karan Johar welcomed Balan on Twitter, saying, " My "Mitwa" friend ( she knows what I mean) is on Twitter!!! @vidya_balan... She deserves all the love!!"
The actress, last seen in Mohit Suri's "Hamari Adhuri Kahani, has ventured into Marathi film industry with a special appearance in a biopic on the late actor-director Bhagwan Dada.
Balan will play the golden era actress Geeta Bali in the film, which traces the Bhagwan Dadas life and the difficulties he faced while making his musical "Albela".