Bachchan did "Ganga", the first part of "Gangotri", three months after his discharge from the hospital in December 2005. He'll be shooting for five days at Film City, taking forward his character of Thakur from "Ganga" after his release from prison.
It's believed that talks are on with Hema Malini, who played Bachchan's wife in "Ganga", to play a cameo in this one.