The actor will take on the role made famous by Amitabh Bachchan in the original 1990 film, which followed the downfall of a gangster.
Roshan told Mid Day: "I am still not interested in doing remakes and I don't think I will ever do a remake.
"When I was narrated the script [by director Karan Malhotra], in ten minutes he made me forget that it was a remake and made me forget all the symbolic visuals I had in mind and I just reacted as an actor. I am very, very proud to be associated with this film."
Roshan added: "I am just driven by my instincts. Whatever my mind says, my instincts just take over.
"He just made me forget about all the emotions I had about this film and he took me to a completely different world, with a completely new character."
The first film was produced by Johar's father Yash Johar and took its title from a poem by Bachchan's father.
In July, Johar claimed that his pairing of Krrish co-stars Priyanka Chopra and Hrithik Roshan will be the most "intense" seen on screen.
> Hrithik Roshan: 'Don't call me a superstar'
Watch the trailer for Agneepath below: