Mark Wahlberg opened up about his battle to pile on the pounds.
In a recent interview with ET, the 50-year-old star opened up about physically transforming for his latest role, real-life boxer-turned-priest Father Stu.
The often-shredded Wahlberg packed on a whopping 30 pounds to play the Father - and he did it in just six weeks.
"I tried to do it in a healthy way," he explained. "It was a dozen eggs and a dozen pieces of bacon, two baked potatoes, a Porterhouse steak, two bowls of white rice, and a glass of olive oil."
Yes, you read that right. The actor was actually drinking olive oil by the glass in order to up his calorie intake.
He continued: "The first two weeks were high proteins. The second two weeks were a lot of carbs. The last two weeks starches, and then sodium, just to kind of get as bloated as possible."
While having to gain weight may sound like a dream come true for many people, for Wahlberg it wasn't long before it became a torturous process.
"None of it was fun, except for the first meal was amazing, because I hadn't eaten anything up until that point. But after that, when you're already full and you have to eat again, and at my age it's just not a healthy thing to do," he said.
By the end of the process, the actor was putting away 11,000 calories a day. Even then, he didn't give up his morning workout routine, saying he used the exercise to work up an appetite rather than to lose weight.
"I had to get up the appetite, so I would go in there and try to lift as heavy as possible just to get hungry. And then I'd have the weight gainer shakes as well and all that stuff," he said, adding: "But none of it was fun. There's nothing worse than when you're full from the last meal and you have to eat again."
This is not the first time Wahlberg has opened up about the process.
Speaking to Jimmy Fallon during an appearance on The Tonight Show last year, the actor said: "It was fun for about an hour. It's such a hard, physical thing to do."
He added: "Losing weight, you just kind of tough it out - you just don't eat, and exercise. And this, even when you're full, I would wake up after a meal and have another meal. I was eating every three hours. It was not fun."
Later in his interview with ET, Wahlberg went on to talk about how his Catholic faith motivated him to make Father Stu - the story of an ex-boxer who finds God after a near-fatal motorcycle crash and resolves to become a Priest.
As well as drawing on his own faith, Wahlberg sought the advice of co-star and fellow Catholic Mel Gibson, whose work on the 2004 film The Passion of Christ also inspired him to tell Father Stu's story.
Father Stu hits cinemas next month.
