MONTREAL - To summon the bloodlust that would help him play a man who bludgeoned Nazis to death in Quentin Tarantino's new war movie, Eli Roth called upon the horrors visited on his relatives in wartime Europe, the injustices he'd felt in life ... and the music of Hannah Montana.

"You couldn't ever put me in a Hannah Montana concert with a baseball bat or I would wipe the place out," joked Roth, who plays Sgt. Donny Donowitz, one of the most feared Nazi hunters in "Inglourious Basterds," which opens on Aug. 21.

Roth, who collaborated with Tarantino in 2007 on "Grindhouse," is probably best known as the writer and director of the "Hostel" horror film, which has been described by some critics as the scariest movie of all time.

"Inglourious Basterds" tips its hat to history but is a typical Tarantino flick, complete with his mix of homages and film styles, blending spaghetti westerns with caper films and French New Wave cinema, for example, in its 152 minutes.

The "Basterds" of the film's title are a group of Jewish U.S. commandos led behind enemy lines during the Second World War by the drawling Lt. Aldo Raine (Brad Pitt), who tells his squad, "We're in the Nazi-killing business and business is booming."

One of the most ruthless members of the squad is Donowitz, nicknamed The Bear Jew by the Nazis. While more than capable at dispatching the enemy with bullets and blades, his weapon of choice is a baseball bat, which he swings with psychotic fury.

Getting into a mindset to wield that bat with such abandon took a lot out of Roth, who said in an interview with The Canadian Press he had to explore some dark places to get into character.

He pointed out that while his grandparents from Poland, Austria and Russia did survive the war, "all my other relatives that didn't get out were killed in the Holocaust."

"So you really think about that," he said. "You think about the most painful things that have been done to you and really awful things that you've done to other people. . .

"You conjure it up and make it feel like it happened 15 minutes ago and you have to stay in that state."

He said he remembers discussing the method with Pitt, who used the same technique on 2006's "Babel."

"He couldn't stand it because he just had to be worked up and upset for 12 hours a day. When they yelled `wrap' at the end of the day, that stuff is very real. It stays with you."

And then there was Roth's music playlist.

Roth put together a heavy metal-hard rock compilation with such groups as Guns N' Roses, the Misfits and Iron Maiden to pump him up for Donowitz's scenes.

As a joke, his girlfriend slipped in a Hannah Montana song.

"I went back and forth thinking about my relatives being killed in concentration camps to listening to Hannah Montana," he said.

He said the unidentified song made him miss his girlfriend the more he listened to it and upset him to the point he became quite emotional, then embarrassed about being emotional -- and then worried.

"I was like, `Wow, what if Brad Pitt caught me listening to Hannah Montana?"'

But it worked.

"You have to let yourself go insane. It's very bizarre. There are certain songs you don't expect to trigger what you need and then it just comes on randomly and you're like `Oh my God, that gets me in the place I need to be.'

"So thank you, Miley Cyrus," he added with an incredulous laugh. "You make me want to kill."

Roth, who burst onto the film scene at the Toronto International Film Festival in 2002 with his debut movie "Cabin Fever," did double duty on "Inglourious Basterds," creating the film-within-a-film "Nation's Pride," a propaganda movie that glorifies a German sniper.

Roth, who is effusive in his praise of Tarantino, said the director was ecstatic with the final result.

"I wanted it to look and feel like a real battle film," he said. "While we're shooting, we're like, `This has to impress the Fuehrer. Hitler's going to see this, guys, come on.'

"But it was quite a thrill to be a Jewish director in Germany making a Nazi propaganda film. I never thought I could be more offensive than "Hostel 2" and somehow I outdid myself."

Quentin Tarantino drops by MTV LIVE in Toronto on Wednesday, Aug. 12 at 6 p.m. ET to discuss the release of his upcoming film "Inglourious Basterds."