Before he prepared for the glory of "300," Gerard Butler had a bit of dilemma on his hands: He was merely aware of the works of the acclaimed graphic novelist Frank Miller, but not necessarily versed in them.

"I knew of Frank Miller, his credibility and the respect that he had. But I hadn't been a comic book reader," Butler recalled in a recent @ The Movies interview. "In fact, it wasn't until 'Sin City' that I started to take a little more interest."

But it didn't take long before the seasoned Scottish actor -- who played the title role in the film adaptation of Andrew Lloyd Webber's stage musical "The Phantom of the Opera" -- to get excited about trading in his Phantom half-mask for the battle helmet of the venerable king of Sparta, Leonidas.

"After I sat down and read '300,' I just thought, 'What have I been missing?' This world of comic books is insane. His comic books, his graphic novels are just wicked," Butler enthused. "I didn't realize that you could get quite so dark and masculine and formidable just through drawings and dialogue on a page."

Based on Miller's graphic novel with artistic partner Lynn Varley, "300" chronicles the epic Battle of Thermopylae in 480 B.C., as King Leonidas and his 300 Spartan warriors unflinchingly head off an invasion by Xerxes (Rodrigo Santoro) and his massive Persian army -- and inspire Greece to rise up because of their valor and sacrifice.

The film, which also stars Lena Headey, Dominic West and David Wenham, opens in theaters and on IMAX screens Friday nationwide.

Mounting The Battle

While it's Miller's name that most people associate with the graphic novel, Butler would have been remiss not to boast about Varley, who brought the author's story to life through her artwork. And even more amazing, Butler said, is how director Zack Snyder channeled their work and realized their collaborative vision on the big screen.

"For Zack to take it as far as he did -- it's almost like Stephen Hawking coming along and working on the ideas of Albert Einstein," Butler mused. "It's one genius after another taking a process and sending it even more beautifully into the world of flowering and dark imagination."

But even with the talent behind the project, Butler knew that he had his end of the deal to hold up, too, by representing King Leonidas a larger-than-life figure that would resonate with audiences. The amazing thing is, when you see Butler command the screen with his burning charisma throughout the entire film, it's hard to believe that in the back of his mind he's always worrying about not disappointing Miller.

"I would be lying if I didn't say that one of my big motivating factors is fear and paranoia, and not wanting to f--- things up," Butler said with a laugh. "That's a great way to give you more a generalized power and motivation. But when you get specific, that's the point where you need to let go and take risks. You'll never take any risks if your only fear is of failing, because then what you'll try to do is answer all the questions of everybody else."

And while Butler is far from being a failure in this role, he does admit failing isn't always a bad thing if it allows you to build character. But that's not to say Butler tries to fail intentionally ...

"You'll never truly improve unless you fail first, that's the only way you learn," he said. "But I say that more as a life rope. I didn't really have the opportunity (on my films) to say, 'You know what? Let me fail and see if I learn from this.'"

A virtual pane-by-pane adaptation of the graphic novel, "300" is unique by Hollywood standards in that most of it was filmed in front of a blue screen. And while Butler and his co-stars had every confidence that Snyder would backfill the sprawling vistas, kingdoms, environments and weaponry of the ancient world with an impressive arsenal of computer-generated effects, the actor was still blown away by the completed project.

"The adrenaline rush leaves you worn out but profoundly moved and inspired," Butler said. "I don't think any of us realized that it was going to turn out quite that amazing."

Getting Ripped

It doesn't take any more than a quick glimpse of Butler in a production still or movie clip to see that the actor underwent an amazing physical transformation for the film.

But the incredibly challenging regimen of building up his abs to an eight-pack and fine toning other muscles wasn't just about expressing the physical manifestation of King Leonidas, but conditioning the actor's mind for the role.

"The training became important for many reasons and not just building the body, but in terms of proving myself as a leader. And not just a leader of others but a leader of myself, that I could take control and really be like a Spartan," Butler said. "I was so inspired in my research to find out what it took to become a Spartan and what endurance they had to go through. I used that motivation, but I also knew every way I pumped -- every extra 10 seconds that I held my body rigid on the rings -- was going to only enhance my performance."

And judging by his appearance in the film, the dedication to his physical being not only enhanced his performance -- it transcended it.

"When I stood up there, I felt all powerful like a lion, like an animal -- not just because of the way I felt I looked and the strength that I felt inside and what I felt capable of at that moment," Butler said. "It was not only about the physical side of things, but the control and power."

And his body wasn't the only thing to become strengthened by becoming Leonidas -- his vision was, too.

"It's a great role. It's the journey of the 300, but so much of it takes place through the mind and attitude of the king," Butler said. "It's a great to experience all of those Spartan dreams, but to have it be seen through the eyes of the king -- it was a big challenge to take on, but I love challenges."