Mark Wahlberg has admitted his efforts to gain weight for an upcoming film role weren’t quite as much fun as he was originally hoping.

Earlier this year, Mark revealed he was deliberately trying to gain 30lbs in the space of six weeks to play boxer-turned-priest Father Stuart Long in the biopic Father Stu.

The Transformers star – who went viral in 2018 when he shared his meticulous fitness regime – told US talk show host Jimmy Kimmel at the time: “They want me to [gain weight] as healthy as possible and I’m like, ‘Dude, I’ve been on such a regimen for so long, I just want to eat everything in sight’.

“I want to go bakeries. I want to go to [US diner chain] Denny’s. I want to get pancakes. I want to get everything I can possibly get my hands on.”

However, it turns out that his efforts were a bit more of a slog than the 50-year-old anticipated.

Mark told Jimmy Fallon on Thursday night: “Unfortunately, I had to consume, for two weeks, 7,000 calories, and then for another two weeks, 11,000 calories. And it was fun for about an hour.

“It’s such a hard, physical thing to do. Losing weight, you just kind of tough it out… [but] 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.”

He added that having recently turned 50 made things even more troublesome, adding: “​​Once the metabolism starts to slow down, it gets really difficult. [But] 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.”

Watch Mark’s Jimmy Fallon interview below:

It was announced last year that Mark is among the highest-paid actors in the world, behind Ryan Reynolds and Dwayne “The Rock” Johnson at numbers two and one on the list, respectively.

Father Stu will mark the directorial debut of Rosalind Ross, the screenwriter, actor and long-term partner of Mel Gibson.