Veteran actor Rajesh Khannas last film Riyasat, which he shot for before he passed away on July 18, will release in India on December 28, a day before his 70th birth anniversary. The late superstar had a prominent role in the movie. Director Ashok Tyagi says the film is almost ready, but he wanted to release it on Khannas birth anniversary. Tyagi also says that Khanna has left a letter behind, which shall be opened just before the release of the film. Kakaji has left a sealed letter behind him, which he wanted us to read before the release of the film. So we will be opening his last letter either on his birth anniversary, or just before the release, he reveals. We have no clue what he has written in the letter, he adds. For his role in Riyasat, Khanna is said to have watched the DVD of the 2005 Amitabh Bachchan-starrer Sarkar. Riyasat also features Gauri Kulkarni, Aryan Vaid, Aryeman Ramsay and Raza Murad.