Ghantasala was called to render the songs. K V Mahadevan was responsible for the music. Rama Naidu was producing a film called 'Prem Nagar', with Nageshwar Rao and Vanisri as lead actors. Ghantasala, towards his end, was having lot of health issues.
To give you an idea about how important Ghantasala was to producers and directors, let me narrate an incident that SPB himself told in a TV program. You don't hear these much in other languages (you may get slokas or viruthams but not padyams. The bhakti songs he sang for these mythologies still reverberate all across Andhra and Telengana. His padyam renditions were much awaited by his fans.
Most importantly, the mythologies were served well by the voice of Ghantasala. The Mythology movies were helped enormously by the presence of NTR, who became Lord Krishna for everyone and other stalwarts like S V Ranga Rao, who was incomparable in roles like Duryodhana, Keechaka, Hiranyakashipu and Ravana. The movies made in those times included Mythology, Historical, Social and Comedy. You can observe Ghantasala's grip on Hindustani ragas) The music directors were ready to set challenging tunes, like 'Siva Sankari' of Pendyala Nageshwar Rao for example, because they were sure that Ghantasala would deliver it flawlessly.
He was 'the' voice of NTR and Nageshwar Rao. Not only the listeners, the whole of film industry was in awe of his voice. His strong voice, combined by his felicity in rendering classical ragas as well as his amazing rendering of padyams, made him a demigod in Andhra Pradesh. Ghantasala, short for Ghantasala Venkateshwar Rao, was a singer whom Telugu listeners worshiped. P.B.Sreenivas, Madhavapeddi Sathyam were some of the male singer but the man who dominated Telugu Film Music went by the name of Ghantasala. P.Leela, Jiki, S Janaki were the other popular singers of those times. As far as singers were concerned, the leading female voice was that of Susheela. Other music directors like Master Venu, T V Raju, Chalapathi Rao and S P Kodandapani were active during these times, the last mentioned being the one gave SPB his first break and later encouraged him a lot. The popular music directors included K V Mahadevan, S Rajeshwar Rao, Pendyala Nageshwar Rao. In 1967, the leading stars of Telugu films were N T Rama Rao (NTR) and Akkineni Nageshwar Rao (ANR). So we can say that people heard SPB first in 1967. He recorded his first song for 'Sree Sree Maryadaramanna' in Dec 1966 (according to Wiki). The idea is to give you a picture about the Telugu film music scene when SPB made his appearance.
You must be surprised as to why the first part of this series is titled, ' A Legend called Ghantasala'. I will occasionally be making reference to some of the singing shows he did for different TV Channels. I will not be concentrating on other aspects of SPB like his acting or dubbing career. I plan to do a multi part series on SPB, tracing his music career in Tamil, Telugu and Kannada film music. Ghantasala Venkateswara Rao (Photo source: Quora)