PM Modi shared an audio on Twitter, where he is heard reciting a poem by the 74-year-old actor.
"A special message from Amitabh Bachchan on Swachh Bharat," Modi tweeted.
The star retweeted PM's post by captioning it "My most gracious and respectful thanks to the honourable Prime Minister Mananiya Shri Narendra Modi-ji, for acknowledging my small contribution."
Bachchan also featured in government's video against the practice of open defecation, launched as part of Centre's Swachh Bharat Abhiyaan, which showed him asking people to join the movement.