Can't blame the young director since his hero is the grandson of the legendary showman and it's only natural for him to follow in his footsteps.
Interestingly, this seems to be more than just a coincidence. Like RK kissing his favourite co-star Nargis in his 1951 classic, the actress Ranbir is kissing in Rockstar's poster is also named Nargis.
Never mind if her surname is Fakhri, but the RK production's inspiration appears to be perfectly followed by the Kapoor scion. And we like it!