Mark Wahlberg Talks 'Difficult' 30-Pound Weight Gain for 'Father Stu' : 'I'm Not Getting Younger'

Mark Wahlberg isn't a fan of making body transformations for movies.

The 50-year-old actor appeared on Australian radio show Kyle & Jackie O where he opened up about his "difficult" experience gaining weight for his role as a boxer-turned-priest in the upcoming film, Father Stu.

When hosts Kyle Sandilands and Jackie 'O' Henderson asked Wahlberg whether it was easier to lose weight or gain weight for a role, he admitted, "I would say it's easier to stay in shape than it is to get in shape."

"I put on 30 pounds… that was really difficult," he explained, reflecting on his physical preparations for Father Stu. "I'm not getting younger."

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Wahlberg previously detailed the film-related weight gain during his July appearance on The Tonight Show, revealing that the process was "fun for about an hour."

"Unfortunately, I had to consume, for two weeks, 7,000 calories, and then for another two weeks, 11,000 calories," he told host Jimmy Fallon. "It's such a hard, physical thing to do. 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," Wahlberg added. "It was not fun."

Walhberg also noted at the time that gaining and losing weight for a role has become harder with age.

"Once the metabolism starts to slow down, it gets really difficult. I was trying to get this movie made for six years, we only had 30 days to shoot it, and so I wanted to really make it happen," he said. "And [I] was also crazy to have financed a lot of it myself. So I knew I was on a ticking clock on my own dime, and you get things done pretty quickly when that's the case."

In May, The Departed actor gave his followers a look at the progress, sharing a photo of his muscular physique side-by-side with a photo of his weight gain look.

"From left photo 3 weeks ago to this, now. Thanks to @chef_lawrence_d cooking," Wahlberg captioned the Instagram post.

His shocking transformation received an abundance of responses in the comments section, including from his wife, Rhea Wahlberg, who wrote, "and it looks just as hot in person baby ❤️."

Wahlberg gave another weight-gain update on Instagram at the time, sharing a video of himself showing off his six pack — which had yet to fully disappear — while at the gym with a friend.

"Kenny's down 50 and I'm up about 20 😂 Inspired to be better!" he wrote. "I'm going up another 20. Yes it's for a role. ✝️🙏❤️."

Father Stu hit theaters April 15.