On TV: Part One of “The Pacific” airs on HBO at 9 p.m. on Sunday.

War is hell. Fact.

And for the actors who star in HBO’s stunning epic follow up to “Band of Brothers,” “The Pacific,” filming a war is almost as hellish.

Before shooting the 10-episode miniseries produced by Tom Hanks and Steven Spielberg, a startlingly realistic portrayal of the Pacific Theater of World War II, the actors had to go through boot camp. Stars James Badge Dale, 31, and Joseph Mazzello, 26, figured it wouldn’t be so difficult — more an actor’s boot camp with catered lunch and comfy beds. Or so they thought.

“I’ve been wrong about things in my life,” said Mazzello, a Poughkeepsie native living in California, who plays Pfc. Eugene Sledge, “but I have never been so wrong about anything.”

Dale, a long-time New Yorker who portrays Pfc Robert Leckie, said that the boot camp was intended to put the actors in the mindset of the actual soldiers: beaten down by the elements and the nature of the combat.

“As much as it is about learning your weapons and learning all the period equipment, getting certain things technically right, the idea was to break us mentally, spiritually and emotionally,” Dale said.

Mazzello said that military aficionados should be pleased that the actors went through serious training with three hours a sleep a night, eating rations, digging ditches, carrying 40 pounds of equipment on their backs through the jungle in 110 degree heat.

“For us to play Marines, Marines and people who are really military enthusiasts really want to know that the actors got the hazing that’s required. They want them to be tough.”

Re-creation

“The Pacific,” like “Band of Brothers,” is a painstaking recreation of the World War II campaign. The characters — Sledge, Leckie and Sgt John Basilone — are real and stories are based partially on the memoirs of Leckie and Sledge, and take viewers on a grueling tour of the war, from Guadalcanal through to Iwo Jima and Okinawa.

To get to really understand their characters, both Dale and Mazzello read the memoirs as well as met with their character’s real-life families.

“[Leckie] passed away in 2001,” Dale said. “I spent a lot of time with his wife, daughter and two sons. They’ve been kind enough to let me into their home. Robert Leckie was a tough character to prepare for because he was kind of a very ironic man. There’s two sides to him that kind of push and pull. There was this loud, Irish New Jersey macho kid and then this very quiet artistic soul.

“I was really struck with the feeling that Robert Leckie wouldn’t want me playing him because he would want to play himself,” Dale added. “That’s the type of guy he was.”

Likewise, Mazzello met the family of Eugene Sledge, who also died in 2001.

“When I spoke to his sons, I felt like I was talking to him because they’re so much like him,” he said. “I felt his personality and his attitude and his humor. I could feel it all through them.

Harsh conditions

Watching “The Pacific” is not easy. It’s violent, tense and gruesome. And it puts the viewers into the mindset of the real soldiers while creating a compelling drama.

All of that made for a rather difficult shoot.

A foot and a half of mud. Nights with rain. Days with 110 degree heat. Running across airfields with boots so thin they were like slippers. Those were just some of the conditions Mazzello said the actors had to endure.

“We spent two or three weeks on that airfield just running,” he said. “Just running. Carrying the base plate. Carrying the pack. Just running. I was in the best shape of my life. All I wanted to do was eat doughnuts when I got home. And I did, successfully.”

Dale recounted a story where Hanks, after watching filming had wrapped, said to the actors that the footage looked “really good.”

“Then [Hanks] says ‘You know, the other day I was watching and I remembered, oh my goodness, you guys are actors. Wow this must have been a real pain in the ass to shoot,’ ” Dale said.

Beyond the physicality, there were also the emotional aspects of the shoot. The series was shot in Australia, thousands of miles from home, and then there was the sense of responsibility to the soldiers’ families.

“All of these things together made it an extremely difficult shoot,” Mazzello said. “But I think the difficult shoots are the ones that turn out to be the most rewarding. That responsibility that we felt every time the mud got too thick or the sun was too hot or the rain was too heavy, we would think of the real guys, the guys that we’d owed something to. The families that were trying to protect their legacies of the people that they loved.

“We would just remember that and that was the thing,” Mazzello said. “One more step.”

Recommended Reading

Want to get more in depth about the WWII pacific campaign? Here are some of books to check out:
• “Helmet for My Pillow” by Robert Leckie
• “With the Old Breed” by Eugene B. Sledge
• “China Marine” by Eugene B. Sledge
• "The Pacific” By Hugh Ambrose

Next Deployment

Following “The Pacific,” both James Badge Dale and Joseph Mazzello have some high-profile gigs. Dale will be starring in the upcoming AMC show “Rubicon” and Mazzello is starring in David Fincher’s Facebook movie, “The Social Network.”