According to reports, six cases have been registered under the Copyright Act.
A press conference has been arranged at 1.30 p.m. to reveal details of the leak.
Meanwhile, Balaji Films, the producer of the movie, has decided to prepone the film's release to July 15.
Trade analyst Taran Adarsh too tweeted about the same saying, "#GreatGrandMasti to now release on 15th July."
The Indra Kumar directional, which stars Riteish Deshmukh, Vivek Oberoi, Aftab Shivdasani and Urvashi Rautela was earlier slated to hit theatres on July 22.