Akhtar, 70, last wrote the screenplay of Shah Rukh Khan starrer 'Don', which was the remake of hit 1978 film of the same name penned by the lyricist and Salim Khan.
"I have been writing lyrics for quite sometime because that was more convenient. The difference between writing a song and a film script is that of a marathon and 100 yards. In 100 yards, it ends early while in marathon it is long," Akhtar said at a session during the Kolkata Literary Meet here.
The celebrated writer has in the past co-written a number of hit films including 'Deewar' and 'Sholay' with Salim.