Forest Whitaker has shed new plot details about Francis Ford Coppola’s mystery project “Megalopolis,” which is set to start shooting in August.

The actor-producer, who is in Cannes to receive the festival’s honorary Palme d’Or, suggested he had a substantial role in the new movie, and spoke favorably of Coppola’s script, which is a long-gestating passion project that’s been in the works for 20 years. Coppola invested more than $100 million of his own resources to make the film, which is his first as a director since 2016’s “Distant Vision.”

“The cast is coming together,” said Whittaker, who praised Coppola as an “amazing filmmaker” that he was excited to work with. The “Last King of Scotland” Oscar winner will star in “Megalopolis” alongside Adam Driver, Nathalie Emmanuel and Jon Voight.

The movie’s plot has been something of a mystery, with Coppola saying in the past that it will be made in the tradition of a Roman epic but set in a utopian version of New York City called New Rome.

Whittaker — who was speaking to media on Tuesday ahead of the festival’s opening ceremony, where he’ll receive his honorary Palme — also shared new details about the plot, noting that “the story deals with the city and the power structures within it, who are fighting for power. One is more progressive.”

“I like the script and I like him,” said Whittaker of Coppola while smilingly talking about the project, budgeted just south of $100 million.

Whitaker previously won the best actor award at Cannes for his performance in Clint Eastwood’s “Bird.” Besides “Bird,” he has also starred in three other movies that have competed at the festival: Bill Duke’s “A Rage in Harlem,” Abel Ferrara’s “Body Snatchers” and Jim Jarmusch’s “Ghost Dog: The Way of the Samurai.”

The actor — who appeared reserved as he took questions from journalists — spoke reverentially of the festival, explaining that when he first came to Cannes in 1988 for “Bird,” he was “acknowledged as an artist internationally. It allowed me to be seen as an artist.”

Whitaker continued: “I’d never really been to a film festival. I was with Clint Eastwood … I was so new. I had just been trying to play that part and now I was here and when I was acknowledged, it touched my heart. It really was a great gift. I remember the night before I was in my room and my brother was with me. He said, ‘They say it’s possible you could win something,’ and I said, ‘Are you serious?'”

Whitaker has also been to Cannes as a producer with such films as Ryan Coogler’s breakout debut “Fruitvale Station” and Chloe Zhao’s ” 2015 film “Songs My Brother Taught Me.”

He is in Cannes this year as a producer on Christophe Castagne and Thomas Sametin’s South Sudan-set documentary “For the Sake of Peace,” which will play in the festival’s Special Screenings section on May 18.

Differentiating between how he approaches producing versus acting, Whitaker said: “As producers, we have to feel like we’re contributing to a dialogue. As an actor, I go by my guts and instincts and personal belief in the world.”

What’s not in the cards for Whitaker, however, is directing. Although he helmed such films as “Waiting to Exhale” (1995) and “Hope Floats” (1998), he said he has “no plans to direct.”

“It takes a lot of time and commitment,” said Whitaker. “It needs to be the proper story … I’m not saying it won’t happen again, just not right now.”