When asked what is the barometer of success for him, Bachchan said, "There is no barometer of success... I don't believe in it. I believe in doing good work."
Recently actor Ranveer Singh had revealed that he got a letter from Bachchan applauding his performance in Sanjay Leela Bhansali's "Bajirao Mastani" which is like a barometer of success for him.
Whenever Bachchan sees a heart-warming good performance on screen, he sends a letter of appreciation to respective actors.
In the past, he has sent letters to Deepika Padukone, Priyanka Chopra and others.
"I like their work and I appreciate. They all are exceptional artists. All this new generation of actors are really good. I cannot resist myself and tell them how good they are...I enjoy watching them. I have admired lot of artists," he said.
"This whole thing of writing a letter, sending messages for a great performance these days... Happens a lot. I am happy they express themselves the way they do," he said.
In his times, celebrities used to either meet and appreciate someone's performance or send a bouquet of flowers.
"There were people who used to meet and appreciate your work. There were times when we used to exchange flowers but I feel and like to write letters. I have always been a great admirer of Dilip Kumar Sahab, I have received a letter from him that I have treasured," he said.
"I feel nostalgic. It's been 45 years in the industry, you are bound to think about so many things," he said.
For the 73-year-old actor, every role that he does today is demanding.
"Every role that comes to us is demanding. It is not correct to say which role is less demanding atleast for me as an actor. We put in effort in equal amount to portray a character on every film," he said. Bachchan is happy that he is getting a variety of roles to play on screen even today at this age. "At my age these are the kind of different characters that you get to play unlike in my earlier years when we were leading actors. At the best you fought the villain, get the girl, that was our life in every film," he said.
"But today we get shades of characters...a man on wheelchair, 13-year-old child, mad guy character in 'Shamitabh'. You get to play wonderful roles that are character-oriented and not leading man. This is how it should be like," he added.
Bachchan will be seen next in "Wazir" alongside Farhan Akhtar, Aditi Rao Hydari and others.