Mirza Asadullah Khan Ghalib wrote:
jii Dhuu.nDtaa hai phir wahii fursat, ki raat din
baiThe rahe.n tasavvur-e-jaanaa.n kiye hu_e
Gulzar changed a word here a pause there and wrote a song around it for Mausam (1975)
dil Dhuu.nDhtaa hai phir wahii, fursat ke raat din
baiThe rahe tasavvur-e-jaanaa.n kiye huye
P.S. Gulzar wrote in an article in "Filmfare" that originally he had not changed "jii" to "dil", but the Music Director of the movie Madan Mohan showed him a copy of Ghalib's diiwaan which had "dil" instead of "jii" in the said Gazal!