It’s a Friday afternoon — exactly one week before his new film “American Assassin” is slated to open in theaters nationwide — and actor Dylan O’Brien is waiting patiently to attend the premiere of the film in St. Paul, Minnesota.

Normally, it’s not the sort of place big premieres outside of Hollywood take place, but this time it’s warranted because St. Paul is the hometown of the Vince Flynn, the late author who created the New York Times best-selling Mitch Rapp novels, including “American Assassin.”

In a phone conversation before the premiere, O’Brien said he expected the premiere — which was attended by Flynn’s widow, Lysa, and their children; producer Lorenzo di Bonaventura; and many of Flynn’s family and friends — to be one of the most emotional events he’s experienced to date. In short, O’Brien was honored to be there to represent the film and commemorate the life and accomplishments of Flynn, who died of cancer in 2013 at age 47.

“Honored is the perfect word for how I feel. It’s going to be really nerve-wracking,” O’Brien said. “It’s really going to be an emotionally-charged night in a way and I’m just really happy to be here, honored to play the character and honored to bring it to his hometown and celebrate.”

Originally released in 2010, “American Assassin” is actually the 11^th Mitch Rapp novel, which serves as a prequel story of Rapp before he becomes the expert CIA agent that readers came to know in the books preceding it.

The film version of “American Assassin” chronicles how a 23-year-old Rapp — who lost his parents in a car accident at age 14 — is recruited to become a counterterrorism agent after he suffers another deep personal tragedy at the hands of Islamic terrorists. Michael Keaton also stars as Stan Hurley, a grizzled black ops veteran who trains Rapp; as well as Sanaa Lathan as CIA Deputy Director Irene Kennedy; and Taylor Kitsch as Ghost — a mysterious figure on the verge of starting a deadly nuclear conflict in the Middle East.

O’Brien has been down the road of adapting well-known books into films before, having starred in the big screen adaptations of “The Maze Runner” novels. For “American Assassin,” the actor said he informed himself of who Mitch Rapp was in reverse, essentially, since he didn’t read any of Flynn’s work before he got the role.

“The script was my first introduction to the role, then obviously I did my research and read about all of the books and the character,” recalled O’Brien, who filmed “American Assassin” after recovering from traumatic injures he suffered during the making  of “Maze Runner: The Death Cure.” “I even went to fan pages to read comments on the character just to get an idea of who the guy was outside of the script. Once we got doing it, I really wanted to build him from the ground up and come from me with the thought that I understood this guy.”

O’Brien said her felt his approach to came from a “really original direction.”

“My goal first and foremost was about really humanizing the kind of cold-hearted Mitch we see in the books. Everyone who knows the books describes him as this cold, ruthless and brutal killer, and I can see why,” O’Brien explained. “But I also saw so much more underneath. I was really excited to bring all these layers underneath to life.”

O’Brien, 26, said that readers of the “American Assassin” novel will notice changes from the page to the screen adaptation, mostly because of the shift in time periods. The actor said the move was made largely to give the story more of a contemporary feel, especially in the age where terrorism is at the forefront of people’s minds.

“You get changes with all adaptations, obviously, and this one’s no different, especially considering how the times have changed with what the book deals with and what we deal with in the movie, “O’Brien noted. “We’re updating and modernizing those situations and events, and done some other major things, too, by adding a major character to the film version. You want book fans all over to approve and hope that what you’ve done still captures that spirit, and hopefully they’ll sign off on those changes, especially in Vince’s hometown, and especially from his family and friends.”

Luckily, O’Brien said, Lysa Flynn was a part of making the film happen, and having her seal of approval meant everything to everybody on the production.

“It really started with Lysa. It’s been the biggest blessing to have her so on-board the entire time with her endless support,” O’Brien said. “She just brings such a warmth to the entire process. She was so happy and so grateful just to come to the set to see the story brought to life. That’s made the process so much easier for us, too.”