The filmmaker says the biggest task for him is to make the movie look real.
In an interview to PTI, Rai says, "It is definitely more special. It (film) is an uphill task and we were all ready for it, be it me or Shah Rukh sir.
"If we don't do it now then when will we do it? The biggest task for me is to keep it very organic as everything is so new around us for everybody, from actors to technical team. The task is to keep it very real."
"His love and confidence shows his affection and that makes me more responsible. The best part is he makes me more confident and it gives me a lot of strength. It shows his attachment to the story.
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"It is great for me to work with such a sensible man and this experience will stay with me life long. This relationship will be with me till I am here."
Rai, 46, says he does not have any performance pressure because of the presence of a superstar in the movie and will stick true to the story.
"I am here to give numbers but that is directly proportional to how we entertain our audience. I think that is the way Shah Rukh also functions. He is a very people's actor and same way I will see to it that we get onto the numbers that are expected from us."
The director adds that today's audience is more inclined towards content and star power of the film does not influence their decision of watching it.
The movie revolves around a four feet tall man and his life. It also features Anushka Sharma and Katrina Kaif.
The film is slated to open in cinemas by the end of 2018.