Filmmaker Anurag Kashyap is all praise for Ranbir Kapoor starer Rockstar, calling it a "soul stirring" film. Kashyap also said it is director Imtiaz Ali's best work till date. Ali has previously given hits like Jab We Met and Love Aj Kal."Rockstar is not so much about rock as it is an individuals story...its another kind of coming of age film..just can't get it out of my head. It is easily Imtiaz Ali's best. This is how a love story should be told. Soul stirring. Still assimilating," Kashyap wrote on his Twitter page.The movie also stars newcomer Nargis Fakhri and follows the story of a small town boy who dreams of becoming a big rockstar."It is unlike most films.. no cacophony of sounds..quiet.. no unnecessary background to propel it forward..Ranbir is just awesome. Such an unexpected film.. does not take any easy route.. does not become a clap trap or a crowd pleaser..It's just so heartfelt," Kashyap added.