According to The Times of India, the actor was reportedly so moved by the cause that he volunteered his services to record the voice-over for an advertisement.
Shivkumar Parthasarthy, director and producer of the breast cancer awareness television advertisement, said: "I wanted to keep the creative clean and symbolic. When I made a rough scratch of the ad, I showed it to Mr. Bachchan with the intention of getting feedback and suggestions as to how I could improve upon it.
"Mr. Bachchan seemed to have liked the commercial, and found the social issue that we were dealing with noble. The rough scratch was a silent plate. We were going to record a voice-over soon when Mr. Bachchan himself offered to give the voice-over."
The director explained: "I was all set to record Mr. Bachchan's voice then and there, but he insisted that we do it professionally, and called me to BR Studios the next morning where he was dubbing for Aarakshan. The voice-over was in my hand in ten minutes flat."
Earlier in the year, Bachchan joined forces with Shah Rukh Khan and Dame Judi Dench to help promote a charity supporting uneducated children in India.
The actor was also presented with a special bus by former Prime Minister Gordon Brown for the creation of a mobile diabetic unit on behalf of the diabetes charity Silver Star.