Apparently, Sajid came on board with Imtiaz and Ranbir to do ROCKSTAR sequel. However, the director-actor twosome was not really keen on doing a sequel and came up with the idea of working on a completely new subject.
However, now that Imtiaz has finalized a subject Ranbir's dates are occupied and he is busy with some other projects. On the other hand, Sajid also knows that Ranbir is the apt choice for this project so he has decided to wait for the actor and keep the film on the backburner.
So, in the meanwhile director Imtiaz and producer Sajid, as per the trade reports, have agreed to start another project with altogether a different cast. And now without much ado Imtiaz & Sajid is all set to start this new project soon.