Robert Downey Jr. appears to have come around to the films of Christopher Nolan.

The Iron Man actor once openly bashed the style of the acclaimed director, famous for his cerebral and innovative films. But Downey has now changed his tune and joined the cast of Nolan's new film Oppenheimer.

Robert Downey Jr. cast in new Christopher Nolan film

As Deadline announced today, Downey is in talks for a role in Nolan's World War II drama about J. Robert Oppenheimer and the creation of the atomic bomb.

We do know that Cillian Murphy will play the lead role, and Matt Damon is also attached to the project, himself fresh off a controversy surrounding his use of a homophobic slur.

As for RDJ's earlier beef with Nolan: The issue dates back to when the Marvel actor got vocal about his dislike of Nolan's Dark Knight trilogy in the DCU.

Christopher Nolan's Most Famous Movies

The star once described The Dark Knight specifically as "a Ferrari engine of storytelling and scriptwriting." He added: "That's not my idea of what I want to see in a movie."

Downey continued: "I didn't understand it. Didn't get it, still can't tell you what happened in the movie, what happened to the character and in the end, they need him to be a bad guy."

He concluded bluntly: "I'm like, 'I get it. This is so high brow and so f–king smart, I clearly need a college education to understand this movie.'"

For Downey, the timing is also interesting, as Nolan is coming off what one could call his "highest brow" movie yet, the divisive 2020 film Tenet. Nonetheless, Downey now looks primed to make his debut in a Nolan project.

Oppenheimer is lined up for a July 2023 release date. You can click here for a look back at Christopher Nolan's best films so far.