WASHINGTON (CNS) — Mark Wahlberg, the Catholic star of the new movie "Father Stu," has been hitting the interview trail to support the film. He's got skin in the game, as he's one of the movie's producers, financing "Father Stu" largely with his own money.

Not that it was his idea to make "Father Stu." Rather, the film found him instead.

Wahlberg went back to his native Boston for a guest appearance on "The Greg Hill Show" on WEEI-FM to tout "Father Stu."

In an April 5 interview that was aired April 6, Wahlberg said it was on a Saturday when he met two priests from Good Shepherd Parish in Los Angeles who met him after hearing confessions for a 5 p.m. dinner — "the old guy dinner," said the 50-year-old actor.

"All of a sudden Father Ed starts pitching me on this movie," Wahlberg said. "And I'm (thinking), 'Why is he pitching me on this movie? Doesn't he have a job?' ... It dawned on me this is something I should be paying attention to ... to take Father Stu's story and bring it to the world."

Father Stu's story, in short, is that of an impulsive renegade who quits an amateur boxing career in Montana to become a movie star in Hollywood. He meets an attractive woman and becomes a Catholic for her.

But a near-death experience convinces him the priesthood is his true calling. As he nears ordination, he is stricken with an ultimately fatal disorder. But he was ordained nonetheless in 2007 and served as an example of unshakable faith, even in infirmity, until his death in 2014.

In an episode of "Conversation with Cardinal Dolan," broadcast on SiriusXM's The Catholic Channel, Wahlberg said: "Probably people thought, what was I thinking? But you know, I prayed about it and every time I did, I just got the affirmation that I need to be making this movie. This movie is a film that is important. It's gonna touch people, and like I said earlier, I think the film chose me.

"So it's one of those things where I'm like, OK, I'm having lots of success, I have this platform, what am I using it for?"

In response to an observation by the show's host, Cardinal Timothy M. Dolan of New York, Wahlberg said Father Stuart Long is still inspiring him long after filming has wrapped on the movie.

"He's still very much hard at work today and challenging me constantly to do more and to do better," Wahlberg said. "I've got pictures of him kind of in my office where I usually do most of my work and every time I glance over, if I'm in a conversation or something, he'll remind me how I need to be approaching the situation."

"I've always talked about my faith, which is good and fine and dandy and people know that," Wahlberg told Bill McGarvey in an interview for America magazine, which posted the article April 6. "But then at the same time, you've got to kind of put your money where your mouth is."

That's exactly what Wahlberg did after a first script failed to grasp the essence of the real-life Father Stu.

He told WEEI he went to talk to Mel Gibson for advice. "Mel had made 'The Passion of the Christ,' a love letter to the Lord, so I wanted to get his opinion on what it was like for him — all the pros and all the cons."

Gibson wound up playing Bill, Father Stu's dad; Wahlberg said Gibson was his first choice for the part. "So we attracted the likes of Mel, and Jacki Weaver (as Stu's mother), and Malcolm McDowell (as his seminary rector). ... They all wanted to bring Father Stu's voice to the big screen," Wahlberg said.

He recalled when he went with the real-life Father Stu and his father and Father Ed — whose surname was never mentioned in the WEEI interview — to see "The Fighter," a 2010 film that garnered Wahlberg a Best Actor Oscar nomination.

Coming out of the theater, "everybody was shadowboxing and stuff," Wahlberg said, but "it was personal" for Father Stu and Bill Long, Father Stu's real father, who was wheeling his son out of the theater. The priest was in a wheelchair by then.

"It was personal to them, they could see that family dynamic in the film. That's what we were going for tonally (in 'Father Stu')," the actor said. "If you could compare it to anything, you could compare it to 'The Fighter.' Cause there's lots of dysfunction, but there's plenty of humor and heart and that's inspiring."

Wahlberg told America "Father Stu" should appeal to all audiences despite its protagonist wearing a Roman collar.

"Tough grace and tough mercy is what Stu earned through his suffering, and through his work and giving back," Wahlberg said, adding the movie means to display "the importance of redemption and rooting for people to change and grow as opposed to turning our backs on them."

Wahlberg said his intent is to "give people hope, and encourage people to pursue their faith, whatever that is."

And Wahlberg clued in WEEI listeners as to how he gained 30 pounds to show Father Stu gained weight as his muscles atrophied.

"When I did all the weight-gaining for this movie, people thought, 'Oh, how fun, you get to put on 30 pounds.' I wasn't eating Wahlburgers all day," he said. (The actor and his brothers Donnie, also an actor, and Paul, a chef, own the Wahlburgers restaurant chain.)

"I went to this doctor, who was supposed to be, like, 'I'm the guy who knows how to do it the healthy way.' And I was just eating stuff you wouldn't want to eat once in a day, never mind eating seven, eight times a day for six weeks," he explained.

The regimen, he said, included olive oil. "You can soak it in rice and all that stuff," Wahlberg said, "but I just chugged it down."