The 72-year-old actor has previously worked with Balki in films like 'Cheeni Kum' in which he played a 60-plus chef in love with a much younger woman and 'Paa', which saw him don the role of a child suffering from progeria.
"Whenever Balki comes to me with a script, my initial reaction is that he must be drunk - his scripts are so unique.
When he narrated me the story of 'Shamitabh' I was surprised.
I had a similar feeling when he offered me 'Cheeni Kum' and 'Paa'. He was very clear about what he wanted from me, including my looks," Bachchan said during the film's trailer launch here last night.
In the film, Bachchan will be seen sporting a rugged, unkempt look. "We got few make up artistes from abroad and they worked with my own make up guy Deepak to create my look with beard."
'Shamitabh' also stars south superstar Rajinikanth's son-in-law Dhanush and will mark the debut of Akshara Haasan, who is the younger daughter of actor Kamal Haasan and Sarika.
"I think each one of them had their own capacity and style and many times when you are working with the legacy of actors or you come from a family of actors the obvious comparisons start. Whether you look like your father, whether you are acting like your brother or you look like your sister. With Dhanush and Akshara I would say - they will create their own legacy," he said.
'Shamitabh' will hit theatres on February 6.
