Kapur, 65, worked with the Sufi singer in his film 'Bandit Queen' where Nusrat lent his voice for a song.
"Nusrat Fateh Ali Khan was the closest I got to God," Kapur posted on Twitter.
Kapur says his songs remind him his shoot with the legendary singer who died of cardiac arrest on August 16, 1997.
"Nusrat saab was like 'I see the film emotion in your eyes' and would look directly at me when he sang for Bandit Queen. Amazing experience Listening to Nusrat sahib everyday that the shoot reminds me to let go of structure and embrace the harmony of chaos," he added.