He wants to get the spoken language, body language, personality and tone just right.
For this John has not only been re-structuring his metabolism and changing his food and exercize habits and watching as many cops films from Clint Eastwood in Dirty Harry to Om Puri in Ardh Satya to Amitabh Bachchan In Zanjeer repeatedly, he has also been socializing with cops trying to understand how their minds and bodies move.
Most importantly, John has been chatting with the Tamil superstar Suriya who played the lead in Kaakha Kaakha.
By sheer coincidence John and Suriya are neighbours in Mumbai. Suriya's wife actress Jyothika owns a flat next to John's residence. And whenever Suriya is in Mumbai he stays a stone's throw away from John.
The two have been bonding big time with absolutely no feeling of illwill or rivalry about the fact that John is doing a role Suriya has already owned and patented in Tamil.
This is the first time that the hero in a Hindi remake has taken the original into confidence. From Vinod Khanna in Dayaavan, the Hindi version of Mani Ratnam's Nayakan where Kamal Haasan starred, to Salman Khan in Wanted, the Hindi remake of the Telugu Pokhiri which starred Mahesh Babu, no leading man has bothered to collaborate with the original hero.
Says John, "Suriya is a great guy and a buddy. Yes we've been bonding about Kaakha Kaakha. I've always dreamt of playing a cop.I've watched Mr Bachchan in Zanjeer so many times I've lost count.
One of the main reasons I wanted to do the Hindi version of Kaakha Kaakha was to get into a cop's uniform. To my disappointment my director Nishikant Kamat decided the to away with the uniform in my film."
So disappointed was John that he tried to argue with his director. "In this matter I am like a child. If I'm playing a cop I want to wear the cop's uniform and feel like a cop."
So adamant is John to get the uniform back that the script is now being re-worked again.
The moustache which Suriya sported in Kaakha Kaakha may also stay after all.
Says John, "I think Suriya looked pretty cool as a cop, mouche and all. I don't know how I look with a moustache. If the people whose opinion I value like me in it, it stays."
Bipasha Basu apparently loves John with a moustache. And that factor has tilted the scales in the moustache's favour.