Modi on Sunday shared an audio file on Twitter, where he is heard reciting a poem by Amitabh.
"A special message from Amitabh Bachchan on Swachh Bharat," Modi tweeted.
The 74-year-old actor re-tweeted to thank Modi.
"My most gracious and respectful thanks to the honourable Prime Minister Mananiya Shri Narendra Modi-ji, for acknowledging my small contribution," Big B tweeted.