The veteran director and actor have collaborated over five times in the past 20 years.
He told New Kerala: "When it comes to favourite actor, the only name I will take is Mr Bachchan. He trusts me a lot as a director.
"So far it has not happened that I have approached him for a role and he has said no. Sometimes it (the films) works, sometimes it doesn't. But somewhere he knows my commitment and that my work comes with lot of seriousness.
"I honestly feel Big B's best performance is done in Nishabd."
The 2007 film, which was inspired by American Beauty, sees Bachchan playing a married man who falls in love with his teenage daughter's friend.
In July last year, Bachchan said that he regretted appearing in Varma's remake of his classic film Sholay.
Varma criticised the Bollywood legend for refusing to make exciting films until his appearance as a crime-fighting legend.