Director Christopher Nolan wasn't holding back with his new film Oppenheimer. Per THR, it's been revealed that the film has been rated R. This marks the first movie to be directed by Nolan with that rating since the 2002 film Insomnia. That followed the R-rated film Memento in 2000. Nolan has notably been sticking with the PG-13 rating in the years since, garnering that rating with films like Inception, Dunkirk, Tenet, and the Dark Knight trilogy. Oppenheimer is also the longest film of Nolan's career, clocking in at just under three hours.

Oppenheimer would also be the first film to be directed by Nolan after his run with Warner Bros., which began with Insomnia. His last movie for the studio was released in the summer of 2020, well into the pandemic era which had heavily affected the movie theater business. The film fell short at box office, at least in part due to the pandemic, and Nolan later left Warner Bros. after criticizing the studio's decision to give their 2021 film slate day-and-date releases, making them available for streaming on Max on their theatrical premiere dates. It was also reported that he was already setting something up a new project with Universal, which was later revealed to be Oppenheimer.

While the rating is harder than what Nolan typically sticks with, there's something that will be familiar for fans when they watch Oppenheimer. Nolan has cast Cillian Murphy in several previous films before giving him the lead in Oppenheimer, which will see the actor playing the father of the atom bomb, J. Robert Oppenheimer. For his part, Murphy has spoken about how thrilled he is to take on a lead role for Nolan.

"It’s the first time he’s cast me in a lead, which I’m still a bit in shock about, but I’m thrilled," he told Esquire. "It’s a huge part and a lot of work. But in my estimation, you’re working with one of the greatest living directors, so you’re in safe hands."

Related: Christopher Nolan Confirms Oppenheimer Is His Longest Movie Yet

Don't Take the Little Ones to See Oppenheimer

Oppenheimer Cillian Murphy
Universal Pictures

Nolan wrote and directed Oppenheimer. He also produced the film with Emma Thomas and Charles Roven. Along with Murphy in the lead, the film also stars Emily Blunt (A Quiet Place), Matt Damon (The Last Duel), Robert Downey Jr. (Dolittle), Florence Pugh (Black Widow), Rami Malek (Bohemian Rhapsody), Benny Safdie (Are You There God? It's Me, Margaret.), Josh Hartnett (Halloween H20: Twenty Years Later), Michael Angarano (I'm Dying Up Here), David Dastmalchian (The Suicide Squad), Jack Quaid (The Boys), Jason Clarke (Terminator: Genisys), and Dane DeHaan (The Staircase).

Oppenheimer will be released in movie theaters on July 21, 2023. That same day, Greta Gerwig's Barbie, a movie that seems to be the complete opposite of something like Oppenheimer, will also be premiering. Some people on social media have declared this to be an interesting box office battle, eager to see which of these films comes out on top.

"This is the first I’m hearing about it, actually. I haven’t paid any attention to that,” star Matt Damon said of the perceived Barbie vs. Oppenheimer feud, encouraging filmgoers to check out both movies, per Vanity Fair. "People are allowed to go see two movies in a weekend. Oppenheimer is one of them!"