The superhero film is currently being promoted across the country by its lead Shah Rukh Khan.
Producer Johar told followers on Twitter: "I just saw RA.One! Adrenalin pumping and the best computer graphics India has ever seen! It's a mega blockbuster super hero ride! Outstanding."
He posted: "The SFX team at Red Chillies and [director] Anubhav [Sinha] have proven that Indian cinema can match and overtake the technology of the west.
"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 Kapoor] is the most beautiful ever! Watch out for the kid Armaan in the film."
Earlier in October, Khan claimed that Johar had been too scared to direct the film himself.
However, the Wake Up Sid producer directed a key scene between Khan's character and female lead Kapoor.
Khan reportedly called Johar and director Tarun Mansukhani in because he was unhappy with Sinha's direction.
Watch the trailer for Ra.One below: