"As you watched the trailer, he (the character) is a frustrated man," said Bachchan who was accompanied by director R Balki and co-actors Dhanush and Akshara Hasan.
The 'Shamitabh' team is in the city for a promotional event of the film, scheduled to be released on February 6.
When asked about his experience of working under Balki, the Big B said "an actor only follows instructions."
"No work is easier in life. People may think that one feels good in front of camera. I have been working in the film industry for many years. Sometimes there remains a fear that what is cameraman thinking of, what is the demand of the script and whether I will fulfil or not," he said.
Bachchan said he had done many films with Balki and the latter is like his family member.
"But when camera starts rolling, we forget mother, father, brother or friends, we only remain actor and feel the character. Whatever has been instructed, we do that," he said.
Asked about his son Abhishek Bachchan once again turning a producer, the senior Bachchan said, "People have their own thinking, Abhishek had earlier produced films ('Paa') and he is also doing acting apart from producing films."
Some parts of 'Shamitabh' were shot in Seven Hills hospital in Mumbai where Bachchan had undergone an abdominal surgery earlier. "Balki insisted to shoot in the same hospital to add element of reality," he added.
On the content of the film, Bachchan parried the question by quoting lines from the trailer, "It is not picture, it is mixture."
Balki said 'Shamitabh' is a story of two egos who clash with one another.
"It is the story of two egos of how two people clash and nobody can be successful indeed. Most people think they can do it alone, most people think they have done it all.
It is not like that. Behind every successful person, there is a team," said Balki, who had earlier directed movies like 'Paa' and 'Cheeni Kum' with Bachchan.
