Christopher Nolan’s next film is a big deal, and not just because it’s about the man who led the effort to create the atomic bomb. For the first time since 2000’s Memento, Nolan is working on a movie that won’t be distributed by Warner Bros., the result of a public falling out between the director and studio after it chose to release its 2021 film slate simultaneously in theaters and on HBO Max. (The only thing Nolan treasures more than the concept of time is preserving the theatrical experience.) Universal Pictures, home of his upcoming J. Robert Oppenheimer biopic—titled, simply, Oppenheimer—has set the release date for July 21, 2023, which just so happens to be the same day that Nolan’s scorned ex Warner Bros. plans to drop its Barbie movie from Greta Gerwig. Oppenheimer and Barbie dueling it out at the box office is already giving us excellent meme material, and it’s honestly hard to decide which project should be prioritized on opening weekend. (Nolan’s film gets the edge if they make a theme song with the hook “Come on Oppie, let’s go party.”)

But even Nolan’s messy breakup with Warner Bros. and a faceoff between a theoretical physicist and an iconic Mattel doll isn’t as intriguing as who the director is bringing along for the ride. If you’ve been keeping up with the entertainment trades, it seems like every single (white) actor in Hollywood has been attached to Oppenheimer. Just when you think Nolan has rounded out his stacked ensemble and couldn’t possibly add anyone else, we find out that one half of Nickelodeon’s Drake & Josh is playing a Harvard physicist who conducted cyclotron research.

With major studios laser-focused on superhero franchises and preestablished IP, perhaps the biggest draw of being cast in Oppenheimer is that it’s a big-budget movie made for adults, an increasingly rare commodity in Hollywood. Whatever the case, this is one of the most star-studded—and somewhat random—casts we’ve seen in a long time. To break down every individual casting choice would require a book instead of a blog, so in the interest of expediency I’ve put together seven tiers to explain why different actors would be drawn to Oppenheimer and what the movie could mean to their respective careers. Let’s dive in.

The Nolan Mainstay Tier

Members: Cillian Murphy, Kenneth Branagh, Gary Oldman, Michael Caine (surely?)

If Universal had its way, I’m betting it would opt for someone with higher star wattage than Murphy to play J. Robert Oppenheimer. But Nolan’s relationship with Murphy goes back to the Dark Knight trilogy—Oppenheimer will mark their sixth collaboration—and this could be the actor’s best chance for some long-overdue recognition at the Oscars. (If Murphy gets nominated, we can all pretend it was for Red Eye.) Assuming Nolan is committed to historical accuracy, this must also mean that Oppenheimer was famous for his dreamy eyes:

Meanwhile, Branagh returns to the Nolan-verse for the third successive film after Dunkirk and Tenet, though it hasn’t been announced who he’s playing. For all our sakes, let’s hope Nolan wasn’t completely enamored of Branagh’s Russian accent in Tenet, which, depending on who you ask, is either amazing or terrible. (Let’s agree on amazingly terrible.) In any case, Branagh’s accent work could make or break Oppenheimer.

Finally, let’s hear it for Gary Oldman and Michael Caine. Oldman is apparently feeling his surname, as he’s publicly mulling a retirement from acting whenever the Apple TV+ series Slow Horses finishes up. Nevertheless, Oldman has confirmed he’s appearing in one scene in Oppenheimer, which I’m sure the Oscar winner will make the most of. But at least Oldman is staying consistent: After hinting that he would retire after 2021’s Best Sellers, Caine reversed course and made it clear that he’s still got some juice left, which was immortalized in tweet form.

The fake-out is for the best—it’s impossible to picture a Nolan movie without a Wild Michael Caine appearing. But despite showing up in eight of Nolan’s films, more than any other actor who’s worked with the filmmaker, Caine hasn’t been announced as part of Oppenheimer’s sprawling cast. A Nolan movie featuring Michael Caine is like Pep Guardiola choking in the Champions League: a sacred tradition that everyone can rally behind. Surely it’s only a matter of time before Caine’s involvement becomes a formality, and if it doesn’t, the rumors that he’s hanging it up will only persist.

The Prestige Tier

Members: Florence Pugh, Matt Damon, Emily Blunt, Rami Malek, Casey Affleck

Here’s a group of actors whose names can sell a project themselves, whether it’s because they’ve got Oscars (Malek, Damon, Affleck) or because they’re in-their-prime movie stars still chasing an elusive win (Pugh, Blunt). Blunt, who has inexplicably never received an Oscar nomination, will probably have the toughest assignment here as Katherine “Kitty” Oppenheimer, J. Robert’s wife, if only because Nolan isn’t exactly renowned for creating complex female characters. (Shout-out to Elizabeth Debicki for trying to make something out of her Tenet character’s entire personality being “I have a son.”)

But the real chaos agent of this quintet could be Malek, who, respectfully, has one of the creepiest on-screen presences in Hollywood. Whether he’s doing hotel commercials or hacking in a black hoodie, Malek has the kind of wide-eyed intensity that belies his slow, just-woke-up drawl. We’ve yet to find out who Malek is going to play in Oppenheimer, but whoever it is, I’m already terrified of them.

The Post-Marvel Tier

Member: Robert Downey Jr.

One of the Marvel Cinematic Universe’s founding fathers finally stepped away from the franchise after 2019’s Avengers: Endgame, in which Tony Stark made the ultimate sacrifice to save the universe. As a result, Downey has a wide-open schedule. Since Endgame, however, the only movie he has appeared in is Universal’s Dolittle, a confounding choice that can only be explained as a cash grab. (Did the MCU not do enough to bump up your net worth, my guy?)

But spending over a decade in the MCU might have caused some people to forget: Downey is a unique and versatile talent. It takes a lot of guts to do blackface for the majority of a movie that satirizes Hollywood and self-absorbed Method actors—let alone get an Oscar nomination for it. A first collaboration with Nolan could prove to be just what Downey needs to reinvigorate his career outside of franchises, assuming he does want to work with more auteurs and perform fewer enemas on dragons.

The Career Revival Tier

Members: Josh Hartnett, Josh Peck, Alden Ehrenreich, Dane DeHaan

Here are four actors whose careers probably haven’t gone as well as they would’ve hoped after some early peaks. For Hartnett, Hollywood Homicide became a self-fulfilling prophecy; Peck has yet to move past his heyday as a Nickelodeon star; Ehrenreich is still looking to rebound from an unspectacular turn as Han Solo in a movie that is better remembered for its behind-the-scenes drama and commercial shortcomings. But even their careers aren’t as all over the place as DeHaan, an actor who always seems like he’s two steps away from a breakout moment that never materializes.

I’ve been a DeHaan Disciple™ since his 2017 double bill of Valerian and the City of a Thousand Planets and A Cure for Wellness, two kickass movies that went underappreciated in their time. (Thankfully, both are starting to come around as cult classics.) But when he hasn’t been in good movies that performed poorly at the box office, DeHaan’s found himself in projects that are just straight-up bad, including an Amazing Spider-Man sequel that killed the Andrew Garfield era and a romantic drama opposite Alicia Vikander that gained notoriety for constantly being delayed. DeHaan’s had better luck on the small screen and currently stars in The Staircase—your regular reminder that ZeroZeroZero also rips—but when it comes to box office wellness, there should be no better cure than working with Christopher Nolan.

The That Guy Tier

Members: Matthew Modine, Jason Clarke, James D’Arcy, Scott Grimes, Christopher Denham, Tony Goldwyn, David Krumholtz, Michael Angarano, Gustaf Skarsgård, David Dastmalchian

We at The Ringer love some That Guys, and biopics are absolute catnip for them. To wit: We ranked the That Guys from First Man in 2018, and one of them—Jason Clarke, currently responsible for a riotous performance on HBO’s Winning Time that has Jerry West demanding an audience with the Supreme Court—is going to be in Oppenheimer. There’s a lot of solid, dependable actors in this group who can thrive despite having a smaller spotlight than their A-list peers; shout-out to Denham, a.k.a. That Guy from Billions. But amid a sea of dudes you know from That Thing, the most intriguing addition to Oppenheimer is Dastmalchian.

His very first film appearance was a brief role in The Dark Knight as one of the men the Joker enlisted to cause a ruckus during the police commissioner’s funeral parade, and the actor credits Nolan for jump-starting his career. (Dastmalchian has since shown up in everything from Dune and The Suicide Squad to Twin Peaks: The Return and The Belko Experiment.) Now, Dastmalchian and Nolan are reuniting for the first time since his big-screen debut, and no matter how small of a role the character actor gets in Oppenheimer, he’ll undoubtedly make the most of it because he’s proved to be a hall of fame role player.

The Promising Youths Tier

Members: Jack Quaid, Dylan Arnold, Emma Dumont, Alex Wolff

Oddly enough, all four of these young actors have made memorable impressions in recent horror movies. In between seasons of The Boys, Quaid was—spoiler alert—one of the new Ghostface Killers in the fifth Scream; Arnold had the distinct honor of being brutally murdered by Michael Myers in Halloween Kills; Dumont fell into a pit of stakes in last year’s underrated Wrong Turn reboot; and Wolff has been tormented by auteurs Ari Aster (Hereditary) and M. Night Shyamalan (Old).

How Nolan will use some of the youngsters remains to be seen. Only two of the actors have had their roles disclosed: Arnold is playing Oppenheimer’s brother, Frank, while Dumont will feature as Jackie Oppenheimer, Frank’s wife and former member of the Young Communist League at UC Berkeley. As for the rest, Wolff seems like a real glutton for punishment, whether it’s getting trapped on a beach that makes you old or watching his on-screen mom decapitate herself with a piano wire. With that gnarly background, I wouldn’t be the least bit surprised if Wolff shows up in one of those fake towns for nuclear testing before a bomb drops on it. (If he wants to survive he’ll have to pull an Indiana Jones and hop in a fridge.)

The Fellow Filmmaker Tier

Members: Benny Safdie, Matthias Schweighofer, Kenneth Branagh … again

When he and his brother Josh aren’t co-directing movies set in New York designed to induce anxiety attacks, Benny Safdie moonlights as a reliable supporting actor—hell, he did a great job doing both in Good Time. The same goes for Schweighofer, the German multihyphenate who introduced himself to American audiences with a scene-stealing turn in Zack Snyder’s Army of the Dead before starring in and directing its spinoff, Army of Thieves. Given Schweighofer’s nationality, his role in a biopic related to the Manhattan Project should be pretty self-explanatory. Safdie, meanwhile, is set to play Edward Teller, the father of the hydrogen bomb, which seems like an even more stressful ordeal than the plot of Uncut Gems.

Of course, we couldn’t talk about filmmakers in acting roles without once again mentioning Branagh, who is coming off Best Director and Best Picture nominations for Belfast this year. (He did end up nabbing Best Original Screenplay.) Presumably, Branagh is just here to act—ideally without an amazingly terrible Russian accent—and won’t try to convince Nolan that Oppenheimer could use some Dutch angles.

Considering the enormous size of the ensemble, it’s hard to imagine there will be any more Oppenheimer casting announcements, especially when the film is reportedly in the middle of production. (Still, it’s not too late, Michael Caine; call up your cinema bestie!) But if anyone else is added to the cast, or if you were just minding your own business when a British American man in a fancy suit approached you and said he wanted you to put on a lab coat for his atomic bomb movie, we will be sure to make note of it.