The 72-year-old actor said the way a sportsman's play gets restricted after a certain age, an actor's work also gets limited due to the physical changes that come with age.
"Like sportsmen don't play too much after a certain age as they are physically weak after a while, similarly when actors get old, their face changes. There comes a time when an actor does not fit certain characters and films.
The evergreen star is the one of busiest artist at his age and Bachchan feels lucky that he has worked with different generations of actors and learnt from them.
"I am gifted by the Almighty that I have worked with four generations and I have learnt so much from all of them. I learn everyday on the sets. The average age of an actor is from 25 to 30 in the industry now and with me there is a difference of 40 odd years. But, I do observe them everyday and try to learn from them," he said.
More From This Section
"Earlier, only Salim-Javed (Salim Khan and Javed Akhtar) used to come with a bound script but now everybody comes with a bound script," he said.
The change which has impressed him the most, however, is the increased number of females in the industry.
"There used to be only heroines and mothers but now there are more women than the males and that's what I like. They all are very efficient and capable in their work right from the sets to costume to the production work."
"We were shooting at the airport and Abhishek landed there at that point of time. He came into the frame and Balki captured him," the actor said.
The father-son were last seen in National award-winning 'Paa'. Bachchan said he would love to reteam with Abhishek if a good script comes their way.
"I hope someone comes with a script for me and Abhishek. Someone has to come with a suitable script and if that happens, we will do the film," he said.
His daughter-in-law Aishwariya Rai Bachchan is making her comeback with Sanjay Gupta's 'Jazbaa'.