The blockbuster action drama “300” is a remarkable film for many reasons, not the least of which was the way director Zack Snyder creatively interpreted Frank Miller and Lynn Varley’s stunning graphic novel for the big screen.

Yet while much of “300” was visually inspired via the wonders of CGI, there were several real elements that stood out to moviegoers — including the physical specimens known as the 300 Spartans led by King Leonidas I (Gerard Butler) as they fought to protect their homeland of Sparta against the advances by King Xerxes (Rodrigo Santoro) and his massive Persian army.

Inspired by the real-life Battle of Thermopylae in 480 B.C., “300” featured numerous actors who put their workout regimens to the test by developing rock-hard washboard abs.

More for work and less for show, the muscular physiques of the soldiers served as a combined symbol of the strength and endurance for the legendary soldiers as they marched shirtless across the rugged Greek terrain to confront their enemies.

Since Butler was leading the crew as Leonidas, the beloved actor took it upon himself to become the real deal instead of allowing his body to be technically enhanced by visual effects.

Gerard Butler’s strict workout regimen didn’t end when the production of 300 began

Warner Bros.

As the 15th anniversary of “300” approaches, Gerard Butler reflected in an exclusive interview with Looper for his new film, “Copshop,” on the crushing preparation he undertook to bring some muscle to Leonidas.

And while the actor and his “Copshop” co-star, Alexis Louder, joked around that his abs were fake in the film (“Everything on me is fake! This is a fake face,” Butler cracked, motioning to his mug), he clarified that he did indeed take to extreme measures to get ripped for the role.

“They were real. I actually could stick my fingers up to there in my abs,” Butler told Looper, motioning to his abdominal area. “I was training for months. I mean, by the time I’d finished, I’d been training for nine months, and I was on a six-hour day regime.”

The training, Butler added, didn’t end when production on “300” began. “Even when I was filming, I was pumping before every take and training at lunch and training at night,” Butler recalled.

“Yeah, I paid the price after, but it wasn’t just for the body. It was also for the attitude … because I kept thinking, ‘These guys were willing to die in any moment, so the least I could do would be willing to die in that moment to recreate who they were.'”

Released in the spring of 2007, “300” went on to earn more than $456 million in ticket sales at the worldwide box office (via Box Office Mojo) and shot Butler’s and Snyder’s careers into the stratosphere.

Butler’s Leonidas appeared in flashback scenes in the 2014 prequel-slash-sequel “300: Rise of an Empire” — starring Eva Green, Sullivan Stapleton, and Lena Headey — which was set before, during, and after the events of “300.”