Big B boarded a Central line train from Chhatrapati Shivaji Terminus (CST) and alighted at Bhandup.
The short trip was for the television show he is hosting, Aaj Ki Raat Hai Zindagi. The show showcases common people and their inspirational stories.
Bachchan Sr travelled with real-life hero Saurabh Nimbkar, who sings on local trains and donates the money thus collected to a cancer charity.
Here's what he tweeted after the journey:
Image Source: twitter/SrBachchan