Dylan O’Brien stars in CBS Films’ American Assassin, in theaters September 15th, 2017. O’Brien portrays Mitch Rapp, a young man recruited to join Black Ops following his fiancee’s murder at the hands of a terrorist organization. O’Brien’s character is trained in the film by Stan Hurley, played by Michael Keaton, to become the ultimate warrior and prevent the deaths of countless innocents.

O’Brien recently spoke with CBS Local’s Matt Weiss to discuss his preparation for the film, working with Michael Keaton and the legitimacy of his facial hair.

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MW- Hey Dylan, how’s it going?

DO- I’m good, really good. How are you?

MW- Doing great! American Assassin comes out September 15th and you’re playing the main character, Black Ops recruit, Mitch Rapp. So we’re going to start with the most important question first, I’ve noticed in a few scenes from the trailer you’re rocking a pretty thick beard. Was that a wardrobe creation or was that all natural?

DO- That was mine! There were a couple scenes we had to recreate it because when you shoot out of order, other scenes will come up down the road that we had to recreate it for. But that was my beard that I showed up for in London for the movie.

MW- Well done, good job on growing that out.

DO- Thank you [laughs]!

MW- Moving on from the facial hair, you were actually recovering from some pretty serious injuries during filming including a concussion and a facial fracture. What was it like taking on this very physically demanding role while you were still recovering from all of that?

DO- It was the hardest thing I’ve ever done. To be honest it was a really difficult time. It was daunting to have this coming up and it felt like it was coming up very quick. I definitely had times of being very overwhelmed with what I was already kind of consumed with in my personal life and knowing that I had this that I was responsible for.

I also wanted to be the best I could for it, I wanted to be in the best shape I could for it and I wanted to have as much time as I could. There were absolutely moments where I was overwhelmed but it was something that ended up being really great for me. I’m really glad that I pushed through and did it because it was something that ultimately became really instrumental in that recovery. It was the biggest challenge of my life but it’s something that will always be really special to me.

MW- You mentioned you wanted to prepare to the best of your ability, what was the training actually like for this role? Was it two-a-days in the gym? Lots of combat training?

DO- Yea it was two-a-days in the gym, a lot of weights in the morning and then fight training in the afternoon, twice a week I did jiu-jitsu. My trainer Roger Yuan was so much more than a trainer to me, to be honest. He was so great at educating me overall, rather than just show me how to throw a punch it was really about educating me on these fighting styles and movement and breathing. He’s not just a muscle packing, punch throwing kind of trainer. It was all about flexibility and movement and speed, just really understanding these different types of martial arts that he was teaching me.

That was it for the most part, obviously we had some limitations in the beginning of training because that was still about four or four and a half months after surgery. As we went on I was able to ramp up more and more. I got more of the go-ahead that I could do more from my doctor and it was just two-a-days for 8 weeks and he (Yuan) stayed with me for basically the whole movie. We would do movement drills on set, I had little weights in my trailer. It’s hilarious it’s the first time I’ve ever had something like that so it was funny.

MW- Being the first time you got to do that kind of training for a project, was that something that drove you to want to take on this role? Or was it more about the other aspects of the character?

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DO- Way more the aspects of the character in terms of who this guy was. When I first read the script I just really felt like the story was there, you know? It was just a great role to me to be honest. I felt like it had strength and it felt really impactful and emotional, it was something that I could believe. I just felt like it had a lot of potential to be something that could be a good business decision but at the same time for me, first and foremost, it’s something that I can also be fulfilled by.

So for me, I was really taken with the arch of the character. I felt it was realistic as well and operating in a really relevant landscape.

MW- Now the movie is based off of the book “American Assassin” by Vince Flynn, was it helpful to you to have that source material to you get into the role or was it more important to you to take make this character your own?

DO- Yea, it was more the latter. I had become aware of the books and how many there were and that this guy (Mitch Rapp) was going to be very much a picture that a lot of people have painted so specifically in their head. It was important to me to be as original as I can with this guy and to have it really come from me and build him from the ground up in my own way, the best that I could.

MW- Very cool. So you’re a young guy, you were 25 when the movie was filmed and you’re 26 now, what was it like for you to be able to work alongside an experienced and well-respected actor like Michael Keaton?

DO- It was awesome, man. It was a dream. He’s someone I always grew up watching and someone I was a huge fan of as a kid. When I started acting he’s someone I remained a fan of and had more and more immense respect for. It was a trip, that was definitely one of the enticing parts of the project and that’s something that coming away from it was one of the coolest things to look back on.

You realize too on a daily basis, ‘Wow cool – this is Keaton,’ but he’s just a normal and down to earth dude. He’s a funny guy, he’s got a really good energy. He’s down to focus when it comes time and take the work seriously but doesn’t take himself too seriously. It was just cool to see how he goes about things. You see his performances growing up translated to screen, especially as an actor you wonder how he achieves that, so it was just cool to see how he goes about it.

MW- That’s great you got to have that experience with him. Well again, American Assassin comes out on September 15th, for anyone who hasn’t already ordered their tickets – can you sell the movie by describing it in three words?

DO- Oh no, that’s impossible [laughs]. How about, “Go – See – It.”

MW- See it’s not impossible, that’s perfect!

DO- All right cool, I nailed it [laughs]!

MW- Thanks for the time today Dylan, awesome talking to you and good luck the rest of the way.

DO- Yea dude, you too. Cheers!

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American Assassin premieres in theaters on September 15th.