Chennai, July 25 : The unit of director Mani Ratnam's much-awaited historical action extravaganza, 'Ponniyin Selvan', on Monday released a behind-the-scenes video of the Oscar-winning maestro A.R. Rahman scoring music for the magnum opus. Rahman, who is seen working with Sivamani and his drummers in the video, asks the percussionist for a particular beat, and he gets what he is looking for. As the drummers build up the rhythm, it is not just the tempo of the score that is raised, but also the expectations from the film. Rahman, who tweeted the BTS video on his Twitter timeline, said: "First Single Coming Soon! PS1 releasing in theatres on 30th September in Tamil, Hindi, Telugu, Malayalam and Kannada!" 'Ponniyin Selvan' is based on the Tamil novel 'Ponniyin Selvan' by the eminent writer Kalki. The story that revolves around the early life of prince Arunmozhi Varman, who went on to become known as the great Raja Raja Chola, is one of a kind. Described by Mani Ratnam as his dream project, 'Ponniyin Selvan' has a star cast consisting of Vikram, Aishwarya Rai, Trisha, Karthi, Jayam Ravi, Jayaram, Parthiban, Lal, Vikram Prabhu, Jayaram, Prabhu and Prakash Raj. The film will be among the most expensive ever undertaken in the country. The film has the best in business handling each of its departments. Rahman is scoring the music, Ravi Varman is behind the cameras, National Award-winning art director Thotta Tharani is in charge of the production design and Mani Ratnam's trusted Sreekar Prasad is back at the editing table. /IANS