EXCLUSIVE: Shia LaBeouf Gets Candid About Painful Real-Life Marine Ritual He Endured for New Film 'Man Down'

This video is unavailable because we were unable to load a message from our sponsors.

If you are using ad-blocking software, please disable it and reload the page.

For Shia LaBeouf's latest military drama, Man Down, in which he stars as a U.S. Marine, the actor decided to add some realism to a scene in which he gets pepper sprayed in the face by opting to use real pepper spray.

ET's Ashley Crossan caught up with LaBeouf at the premiere of Man Down in Los Angeles on Wednesday where he opened up about why he chose to suffer for the scene.

"I'm scared I'm not good enough," the outspoken 30-year-old star admitted. "It's like when you go bowling, [and] you put up the bumpers. You might be able to hit a strike without the bumpers but why not put the bumpers up?"

"The guy who did it to me, this guy named Nick Jones Jr., who is my heart, he is the Marine I went through this whole thing with," LaBeouf added. "He knew how to do it in a safe way, so it just seemed like an easier thing than to have to conjure it."

RELATED: 'Man Down' Director Dito Montiel on Shia LaBeouf’s ‘Crazy Energy’ & Never Knowing What’s Going to Happen Next

According to the star, they only needed to film the scene twice, so he actually got sprayed in the face both times. However, he said the incident wasn't nearly as bad as it sounds.

"We just did it twice real quick. Just really fast," he said. "It wasn't really that crazy… every Marine does it."

LaBeouf's co-star, Jai Courtney, remembered the day they shot the pepper spray scene vividly, and recalled how well LaBeouf actually handled the painful experience.

"He's a trooper. He just went for it but I'm sure it sucked," the 30-year-old Suicide Squad star shared. "I think he'd been worked up a little too much and he was a little too prepared. He was prepared for it to be worse than it was, but he's a tough dude."

WATCH: Shia LaBeouf Is Hitchhiking Across the Country and Calling It Art

Meanwhile, LaBeouf is also feeling the love for his turn in another independent feature, American Honey, which recently earned six Independent Spirit Award nominations.

To promote the film, which tells the tale of a wild trek across the United States, the stars hit the open road for an American Honey road trip of their own.

In fact, LaBeouf even celebrated his 30th birthday in June while promoting the film in Philadelphia, which he admitted was a town he didn't expect to have a great time in, but ended up loving.

To commemorate the occasion, LaBeouf went out for a traditional Philly cheesesteak.

"It was quite cool. And I remember, this is quite Philly, I went there and they gave me a free sandwich and I was like, 'Cool can I get some fries?' and they were like, 'Hell no man, you have to pay for them fries,'" LaBeouf recounted. "That's very Philly."

Man Down
hits theaters Dec. 2.

WATCH: Shia LaBeouf Says He Didn't Like the Movies He Made With Steven Spielberg