Allu Arjun's very first project didn't materialize. Gangotri was not supposed to be his debut. Jayam was meant to be his maiden venture.
Director Teja had planned Jayam with Arjun, then known to him and others in the industry as Allu Aravind's son and nothing more. Teja, at that time, was inclined to work with newcomers. He probably felt that Arjun's face looked innocent and naive to play the coming-of-age college lover boy. The Teja-Arjun combo was something even a section of the media reported about.
However, weeks later, Arjun was replaced by Nithiin. This decision was apparently made without consulting Allu Aravind and Arjun. To his credit, Nithiin did perfect justice to the character. Jayam was a sensational box-office hit.
Writer Chinni Krishna, in a recent interview, revealed that he wrote the script of Gangotri with a vengeance after Arjun was unceremoniously replaced in Jayam. "Gangotri became a blockbuster," he said.
Incidentally, both Gangotri and Jayam milked the prevalent trend, where young lovers defy resistance from elders.
