"I just saw 'RA.One'! Adrenalin pumping and the best computer graphics India has ever seen! Its a mega blockbuster super hero ride! Outstanding," the 39-year-old posted on micro-blogging site Twitter
The film is releasing Wednesday on Diwali.
Made at a budget of over Rs.100 crore, the film is jointly produced by Eros International and megastar Shah Rukh Khan's production company Red Chillies Entertainment. Anubhav Sinha is the director.
"The SFX team at Red Chillies and Anubhav (Sinha) have proven that Indian cinema can match and overtake the technology of the West," Johar further posted.
"RA.One" will see Shah Rukh playing the lead role along with Arjun Rampal and Kareena Kapoor.
Johar also praised the star-cast saying: "Shah Rukh is not only a mega movie star but every inch of his performance is conviction personified. Arjun Rampal makes a stunning impact and my darling Bebo (Kareena) is the most beautiful ever! Watch out for the kid Armaan in the film."