Dylan Arnold had to master some basic physics for Oppenheimer

Dylan Arnold had to learn some physics for his role in 'Oppenheimer'.

The 29-year-old actor stars in Christopher Nolan's film as Frank Oppenheimer - the younger brother of Cillian Murphy's main character J. Robert Oppenheimer – and wanted a basic understanding of the science behind the creation of the atomic bomb.

Dylan told The Hollywood Reporter: "I wanted to have somewhat of an understanding. It still baffles me the way the Oppenheimers' minds work, and it would've been a fool's errand to try to really understand everything on the physics side.

"So I had a general knowledge of it, but what you want to do as an actor is tap into the human element and figure out how this guy feels about all this. And then tap into that passion and that drive, and go from there."

The 'Halloween Kills' star continued: "Fortunately, I don't have to teach any physics classes, and in any situation in which I would, it would be written for me.

"So I knew I couldn't fully understand what these guys talked about, but Chris did a phenomenal job in the movie by allowing you to enter Oppenheimer's mind. It's a really rich character study."

'Oppenheimer' features an all-star cast including Murphy, Emily Blunt and Matt Damon but Dylan felt as if he was always welcome on the "playful" set of the picture.

He explained: "It's hard to not set your expectations high, but they were immediately surpassed when I came on set. It felt like a playful atmosphere. Everyone was so excited to be there. The quality of work from everybody was superb, and you just feel welcomed.

"Sometimes, especially when you're a younger actor, you can come onto these more experienced sets and feel like you don't belong. But from day one, I felt like I belonged.

"He makes it fun, and it's pretty astounding that he's able to keep all this stuff in his head and be as calm and as pleasant as he is when he's running this giant ship. So it was just an amazing experience."