Amitabh, who has woked with Varma in films like "Sarkar", "Nishabd" and "Ram Gopal Varma Ki Aag" among many, tweeted: "https://youtu.be/Tc04wxTfaPY... the RamGopalVarma with his latest ... Pretty astounding!"
The filmmaker responded to Big B's tweet and quipped that the forthcoming film will help him "pour some water on my 'Aag'".
"@SrBachchan Thank u Sarkar! I think with "Killing Veerappan" I really managed to pour some water on my 'Aag'," Varma wrote.
Riteish also heaped praise on the trailer and said that the promo was "outstanding".
"What an outstanding promo: #KillingVeerappan : @RGVzoomin Sir your casting can't get more real than this," the "Bangistan" actor wrote.
Varma, who has helmed movies like "Satya", "Bhoot", "Daud" and "Phoonk" among many "hopes" that "Killing Veerappan" helps him "come back alive".
"@Riteishd Hey Riteish thanx! I am hoping that the dead Veerappan will make me come back alive," Varma wrote.
A multilingual project, "Killing Veerappan" will also be made in Telugu, Tamil and Hindi.
Actor Shivarajkumar will play the central role of the officer who kills Veerappan.
Sandeep, an aspiring youth from National School of Drama, was selected to play the role of the sandalwood smuggler.
The crime thriller also features actresses Yanga Shetty and Parul Yadav.