Born in undivided India in 1927, the ghazal singer, who passed away in a Karachi hospital Wednesday after a prolonged illness, was instrumental in opening up the evocative world of Urdu poetry. He popularised the poetry form as a musical genre for millions of Pakistani and Indian homes in the process.

The soft-spoken man was the uncrowned king of music for Pakistan's movie industry and further raised the profile of the ghazal, once considered passe among elite exponents of Hindustani classical music.

According to an estimate by his son Arif, Hassan gave voice to more than 20,000 songs and, apart from Urdu, also sang in Bengali, Punjabi and Pashto.

Some of his famous ghazal renditions include "Zindagi mein sabhi pyar kiya kartein hain" (written by Qateel Shifai); "Dekh tu dil ki jaan se uthta hai" (by Mir); "Shola tha jal bujha hoon"; "Yeh mojeza bhi mohabbat dikhaye mujhe" (by Qateen Shifai); "Abke bicchde khwaabon mein mile" (Ahmad Faraz); "Baat karni mujhe mushkil" (Bahadur Shah Zafar); Uzr aane mein bhi hai (Daagh Dehlvi)

Born to a family of Kalawant musicians in Luna village, now in the Indian state of Rajasthan, Hassan was musically baptised by father Ustad Azeem Khan and uncle Ustad Ismail Khan, who were Dhrupad musicians.

The family migrated to Pakistan after partition and sank into penury. Eking out a living was difficult. Young Mehdi began to work in a bicycle shop and later became an auto-mechanic.

In his book "Mehdi Hasan: The Man & his Music", Pakistani author Asif Noorani has highlighted this phase of Hassan's life and written that his humility stood tall against the fame and greatness he had achieved later.

"He had earned his living by repairing automobiles during his younger days. During his years of stardom, his harmonium broke and he started repairing it himself, wittingly replying to the people surrounding him that this was a piece of cake compared to the number of engines that he had repaired in the past," Noorani wrote.

The hardships of life notwithstanding, Hassan stuck to his music and continued with his "riyaz". His patience paid off when he was invited to sing for Radio Pakistan in 1957 - first as a 'thumri' singer and then as a 'ghazal' exponent.

Hassan had to work harder than many of his younger colleagues but his innovative approach earned him fame.

Traditionally, ghazals were sung in a thumri-like manner. They were set to ragas like Khamaj, Piloo and Desh. The classical format stymied the scope of the compositions - preventing it from innovating.

However, Hassan pioneered a "ghazal gayaki" that played upon the mood of the music rather than on the classical nuances.

A composer of rare brilliance, he had a flair for using the ragas best suited to the ghazal's appeal.

Hassan's style combined dhrupad, khayal and Rajasthani folk music.

His magic was not confined to Pakistan, he was equally popular in India. In fact, he was one of the first Pakistani ghazal singers who charmed Indian audiences.

His fan following had impressive names - Lata Mangeshkar once described his voice as the "Voice of God" and former prime minister Atal Bihari Vajpayee was a great fan of his melodies.

In October 2010, Mangeshkar and Hassan teamed up for "Tera Milana" in the album "Sarhadein", probably their first and last duet.

In 1978, when Vajpayee was foreign minister, Hassan had performed at his residence.

After shining on the music firmament from 1962 to the early 1980s, Hassan's career started fading as illness took a toll and Urdu films became less popular.

His home country honoured him with several awards and honours - Tamgha-e-Imtiaz, Pride of Performance and Hilal-e-Imtiaz.

The Nepal government too honoured him with the Gorkha Dakshina Bahu.

Hassan, who married twice, is survived by 14 children - nine sons and five daugthers. Both his wives died before him.