You just listen to Ae dil mujhe aisi jagah le chal jahaan koi na ho (Arzoo, 1950), and that says it all.
His first song after he shifted to Bombay from Calcutta , composed by Anil Biswas, is on a different plane. His velvety voice with a unique tremolo immediately put him on a special pedestal. Anil Biswasâs role was not only in composing this all-time great song, but also in putting confidence in Talat Mahmood that the Kampana in his voice was his strength and that he did not need to get rid of it to copy his rivals.
This is also his first recognizable film song, and hence the wide misconception that this was his debut song in films.
Anil Biswas and Talat --
https://www.youtube.com/watch?v=_7LtH-YJ8Os