Bardapurkar said it was Gokhale who recommended Bachchan's name for the film.
"We narrated the story to Mr Gokhle first and it was him who suggested that Mr Bachchan would be suitable for a role like this (of an star).
"He made the call to him and that's when we went and met Bachchan sir and he immediately agreed to be a part of our film," he added.
In the film, Bachchan and Gokhale will be seen as childhood friends.
"They both start their journey together. Bachchan sir and Ghokale sir are school friends and they meet almost after 70 years for a birthday party," Akshay added.
Talking about the film's title, Bardapurkar said, "AB stands for Amitabh Bachchan and CD for Gokhale's character, who is called Chandrakant Deshpande."
The upcoming family-comedy drama will release in December this year.
Bachchan and Gokhale, 78, have previously featured together in cult films like "Agneepath" and "Khuda Gawah".
Bachchan, who started shooting for "AB Ani CD" on Tuesday, is also working on Ranbir Kapoor-Alia Bhatt-starrer "Brahmastra"; "Sairat" fame Nagraj Manjule's Hindi directorial debut "Jhund"; a family comedy titled "Gulabo Sitabo" with Ayushmann Khurrana; and thriller "Chehre" with Emraan Hashmi. PTI