While production has been under way since February, Cillian Murphy has been spotted for the first time on Christopher Nolan’s Oppenheimer with Robert Downey Jr.

The 45-year-old Murphy plays J. Robert Oppenheimer, who developed the world’s first atomic bomb as part of the Manhattan Project in the new movie.

Murphy was spotted filming exterior scenes in Princeton, New Jersey on Tuesday afternoon, alongside Robert Downey Jr., who plays former United States Secretary of Commerce, Lewis Strauss.

Cillian as Oppenheimer: While production has been under way since February, Cillian Murphy has been spotted for the first time on Christopher Nolan movie Oppenheimer with Robert Downey Jr

Here we go! Robert Downey Jr. and Cillian Murphy were spotted for the first time on the set of director Christopher Nolan’s new movie Oppenheimer in New Jersey on Tuesday

Murphy was spotted on set wearing a brown overcoat over a white dress shirt, brown suspenders, brown tie and brown pants.

He also wore a brown fedora with black shoes as he was spotted on set in New Jersey.

The actor was also spotted chatting with his co-star Robert Downey Jr. between takes on the highly-anticipated film.

Cillian’s look: Murphy was spotted on set wearing a brown overcoat over a white dress shirt, brown suspenders, brown tie and brown pants

Chatting: The actor was also spotted chatting with his co-star Robert Downey Jr. between takes on the highly-anticipated film

Downey was spotted in a crisp light grey suit with a grey suit coat, white shirt and grey tie.

He also used suspenders to hold his grey pants up in the film set in the 1940s, while also donning a pair of black glasses.

The actor completed his look with brown and blue boots as filming continues on director Christopher Nolan’s new film.

Robert’s look: Downey was spotted in a crisp light grey suit with a grey suit coat, white shirt and grey tie

On set: He also wore a brown fedora with black shoes as he was spotted on set in New Jersey

Significant: Cillian (pictured March 2020) is stepping into the role of Julius Robert Oppenheimer (pictured right in 1967) who was an American theoretical physicist and professor of physics

The film will be adapted from the 2006 book American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer by Kai Bird and the late Martin J. Sherwin.

The book charts Oppenheimer’s life from his development of the atomic bomb as the head of the Manhattan Project.

Downey Jr. plays Lewis Strauss, who was the head of the Atomic Energy Commission and who actively disliked Oppenheimer.

Going back in time: Robert (pictured April 2018) is portraying Lewis Strauss (pictured right in 1954) who served two terms on the U.S. Atomic Energy Commission

Dislike: Downey Jr. plays Lewis Strauss, who was the head of the Atomic Energy Commission and who actively disliked Oppenheimer

Adaptation: The film will be adapted from the 2006 book American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer by Kai Bird and the late Martin J. Sherwin

Project: The book charts Oppenheimer’s life from his development of the atomic bomb as the head of the Manhattan Project

Nolan will direct from his own adapted screenplay based on Bird and Sherwin’s book, which won the 2006 Pulitzer Prize for Biography.

Nolan will also produce with his wife Emma Thomas and their longtime collaborator Charles Roven through his Atlas Entertainment company.

Universal Pictures has set a July 21, 2023 release date for Oppenheimer, which currently opens against Warner Bros.’ animated comedy Wile E. Coyote.

It will be distributed theatrically worldwide, with Nolan demanding, among other requests, a theatrical window of at least 100 days.

Director: Nolan will direct from his own adapted screenplay based on Bird and Sherwin’s book, which won the 2006 Pulitzer Prize for Biography

Producer: Nolan will also produce with his wife Emma Thomas and their longtime collaborator Charles Roven through his Atlas Entertainment company