Conversation so far:
Which songs did Gulzar write ?
"Mora Gora Ang Layle".
Who was the singer of this song ?
Lata Mangeshkar.
Who else is a singer that sang lyrics by Gulzar ?
Rekha Bhardwaj.
Are there any other interesting aspects about this article?
Song lyrics and poems written by Gulzar gave the poetic attribute and the "much-needed additional dimension" to Ashok Kumar's role in the film.
Which film is that ?
the 1968 film Aashirwad.
Who was the director of Aashirwad ?
Directed and produced by Hrishikesh Mukherjee.

Question: Who is the director he worked with the most as a lyricist ?
Self-contained rewrite: Who is the director Gulzar worked with the most as a lyricist ?