“I sat through 3 hours of ‘Oppenheimer,’ gripped by Chris Nolan’s narrative,” Stone wrote. “His screenplay is layered and fascinating. Familiar with the book by Kai Bird and Martin J. Sherwin, I once turned the project down because I couldn’t find my way to its essence. Nolan has found it.”

“‘Oppenheimer’ is a classic that I never believed could be made in this climate,” Stone concluded. “Bravo.”

Stone is not the only prolific director to publicly praise Nolan’s epic. Before “Oppenheimer” released in theaters, Paul Schrader posted rave review in social media. The “Taxi Driver” writer called Nolan’s film “the best, most important film of this century.”

“If you see one film in cinemas this year it should be ‘Oppenheimer,’” Schrader added. “I’m not a Nolan groupie but this one blows the door off the hinges.”

Oppenheimer has become a box office blockbuster despite its three-hour runtime and R rating.

The film has already surpassed $400 million at the global box office in under two weeks of release. It’s now playing nationwide courtesy of Universal.