Will Graham is the grandson of the legendary evangelical Reverend Billy Graham, and he recently got the chance to portray his grandfather in the new movie Unbroken: Path to Redemption. Now, he is opening up about what the experience of playing Billy was like, and how it brought him closer to the gospel than ever before.

“One of the things I learned from my granddaddy while I was doing this movie is the sense of urgency with the Gospel,” Will said at the premiere of the movie. “My granddaddy would always say, ‘The Bible says…’ and that’s what he was famous for. I loved learning about my grandad’s sermons — he preached a lot different in 1949 than he did in 1999. But, it was still that same commitment to the Word of God. He never slowed down. He was like a machine gun preacher. He would never take a breath.”

The movie tells the true story of U.S. Olympic athlete and World War II veteran Louis Zamperini, who was a prisoner of war in the 1940s. He struggled to readjust to life back home when he was released, and he turned to alcohol. During this time, Louis turned on God and blamed him for all the problems in his life. Things got so bad that his wife Cynthia was ready to divorce him.

“Cynthia was hurting for her husband,” said Will. “She wanted to help her husband. But She didn’t know what to do because Lou didn’t want to be helped. At first, she wanted to divorce him, she just wanted to run away from it. And that would’ve been easy; just cut ties and be gone.”

Cynthia met Billy in 1949, and she introduced her husband to him later that year. The reverend helped Louis rediscover his Christian faith and turn his life around.

“Cynthia had a hope that was contagious,” said Will. “It would finally rub off onto her husband, Louis. It took awhile…but she was able to get him to come to the crusade. He hated everything about it. But the night that he tried to get out, he found himself walking to the front. It was all because of a woman who had not given up on her husband. Marriage is tough, but God can work out the problems in any marriage.”

Billy tragically passed away earlier this year, but Will said that his grandfather would be proud of the way that he portrays him in the film.

“My granddaddy would be excited to know that they’re telling the story about Louis Zamperini and how God can change a marriage,” Will said. “They weren’t the only ones that came to know Christ in 1949, but they’re the epitome of it. That’s for sure.”