Before playing Lt. Col. Bill Kilgore in "Apocalypse Now," actor Robert Duvall, a U.S. Army veteran, persuaded a Vietnam War helicopter pilot to explain the realities of air cavalry life.

To portray Augustus McCrae in "Lonesome Dove," Duval studied equestrian skills with a champion show jumper and befriended West Texas football legend Sammy Baugh, mastering his bowlegged walk and slow drawl.

For his Oscar-winning role as the alcoholic country-music star Mac Sledge in "Tender Mercies," Duvall drove hundreds of miles in rural Texas, studying customs and accents. He formed a band, performed in bars and wrote two songs for the movie.

Duvall visited churches, too -- preparing to embody Sledge's born-again conversion, baptism and faith. Research with believers immediately bled into the screenplay he wrote for "The Apostle," which Duval directed and financed. The movie earned him another Academy Award acting nomination, one of seven during a career that ended on February 15, when the 95-year-old screen legend died at home on his Virginia horse farm.

That movie's complex Pentecostal preacher -- Euliss F. "Sonny" Dewey -- ran from the law after killing his wife's young lover with a baseball bat.

Duvall talked with fallen ministers in prisons and took notes.

"I've met guys like that who have done all kinds of bad things, even murder and rape," Duvall told me, while promoting "The Apostle." These preachers are "real people, and they struggle with the good and the bad that's in their own souls. They're human. I wanted to show the reality of that struggle. ... My guy makes mistakes. But he's more good than bad. He hangs on to his faith, because it's real."

In "The Apostle," Dewey didn't run from God. He screamed his pain in prayers.