Bachchan, 72, who is the brand ambassador of the state, will embark on a multi-city tour for the film.
"Ahmedabad first on 14th...Then a host of other cities — Delhi, Kolkata, Chennai, Dubai, London and perhaps Pune. These are informed promotion acts by authorities that make them.
"They may all come out true or may just fade away with some drastic last-minute changes... Beware...But I do sincerely hope they do not," Bachchan posted on his blog.
Also starring Dhanush and Kamal Haasan’s younger daughter Akshara in key roles, the R. Balki-directed movie is set to release Feb. 6.
Bachchan, who worked on promoting the cause of educating the girl child, also shot Shoojit Sircar’s “Piku” in Gujarat.
"Worked on the promotion of educating the girl child...came across some distressing visuals and stories. Let’s educate our girls. They become the soul of the home. They are the reason for the warmth that embraces us all," he later tweeted.