While appearing on “The Tonight Show Starring Jimmy Fallon” on Thursday night, Hollywood star Mark Wahlberg opened up about his role in the upcoming movie Stu, which required him to gain weight.

“Unfortunately, I had to consume, for two weeks, 7,000 calories, and then for another two weeks, 11,000 calories,” said Wahlberg, 50. “It’s such a hard, physical thing to do.”

Ok so the first look at Mark Wahlberg in the upcoming "Stu" is *actually* worthy of the "x is unrecognizable* headlines. Damn. pic.twitter.com/Hsdg1y8kO2

— Will Mavity (@mavericksmovies) May 22, 2021

“Losing weight, you just kind of tough it out, you just don’t eat, and exercise,” he added, according to Fox News. “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.”

Wahlberg went on to say that gaining and losing weight for a role has only gotten harder with age.

“Once the metabolism starts to slow down, it gets really difficult,” he confessed. “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. 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.”

Men’s Health reported that Wahlberg had said back in May that he planned to gain 30 pounds in six weeks by eating a “20-piece chicken nugget and 20-piece hot wings from Kentucky Fried Chicken with a six-pack of beer.” At the time, Wahlberg seemed excited about this, as he is typically known for his strict regime of diet and exercise.

“I’m like, ‘Dude, I’ve been on such a regimen for so long, I just want to eat everything in sight,’” said Wahlberg. “I want to go to bakeries, I want to go to Denny’s, I want to get pancakes. I want to get everything that I could possibly get my hands on.”

Lawrence Duran, Wahlberg’s personal chef, spoke to E! News about how they were going about the weight gain.

“We meet with a team of doctors who do his bloodwork and a nutritionist who gives us a full breakdown of what his body needs, what his body’s lacking and basically come up with a meal plan accordingly,” Duran said. “We go to a specialist every two weeks to see where we’re at and adjust things,”

“It’s not easy for anyone to take in that much food even though we’re breaking it up into smaller meals. He’s eating about every three hours,” he added. “We do good carbohydrates, dark green vegetables, and then, just switch up the protein throughout the day and, at least, a dozen eggs a day.”