2023's biggest film is getting even bigger, believe it or not. Christopher Nolan's upcoming wartime epic Oppenheimer has seemingly cast just about every notable actor under the sun with more casting announcements coming at a rapid-fire pace. Rivaled only by Margot Robbie's Barbie movie in its cast, the film has just added Olivia Thirlby to the gargantuan ensemble in an unknown role according to Deadline.

Oppenheimer may boast the greatest cast ever assembled, featuring Cillian Murphy, Emily Blunt, Matt Damon, Robert Downey Jr., Florence Pugh, Rami Malek, Josh Hartnett, Kenneth Branagh, Jack Quaid, Matthew Modine, Josh Peck, and even a confirmed appearance by Gary Oldman, and that's only scratching the surface. Murphy leads the crowd as the titular real-life scientist J. Robert Oppenheimer, the so-called Father of the Atomic Bomb in charge of the Manhattan Project. The film is based on Kai Bird and Martin J. Sherwin's Pulitzer Prize winner American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer which recounted the life and downfall of the theoretical physicist as he was forced to deal with the ramifications of his scientific breakthroughs.

It's a massive return to film for Thirlby, who hasn't been a major presence in the film industry for some time now. Thirlby really cut her teeth in the industry with the 2007 Elliot Page, Michael Cera dramedy Juno as the title character's best friend. She eventually went on to star in The Wackness and was later cast opposite Karl Urban in 2012's Dredd, a film she hopes will one day get a follow-up. Most recently, her appearances have mostly been on the small screen. She starred in the ill-fated FX series Y: The Last Man as Hero Brown and in The L Word: Generation Q. Among her other appearances are roles in No Strings Attached, King Goliath, and Above the Shadows which paired her with Alan Ritchson and comedian Jim Gaffigan.

Peaky Blinders Tommy Shelby standing in front of a door

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Oppenheimer is notoriously lacking in details as to how all of these Hollywood stars fit into Nolan's vision and Thirlby is no exception. We've recently had a few faces get matched to names outside of Murphy as Oppenheimer, like Blunt who'll play his wife, and Downey Jr. who'll appear as Lewis Strauss, but there are still plenty of unknowns. The film sees Nolan taking the director's chair with a screenplay of his own making. He'll also produce with the help of Emma Thomas and Atlas Entertainment’s Charles Roven.

Oppenheimer is a ways off still with the film expected to hit theaters on July 21, 2023. With production underway in New Mexico, California, and New Jersey, who knows what surprises Nolan has left, or if there are even actors left to surprise us with.