But now the 22-year-old singer is revealing just how he got his amazing body! In a new interview with Details magazine, Nick says he had to bulk up his formerly skinny frame for his new role as a fighter in DirecTV's Kingdom. And from what he describes, it was not easy.
"I had about six weeks to put on 12 to 15 pounds of muscle before filming started on Kingdom -- my character is a fighter whose strong suits are wrestling and grappling," he explains. "Diet had a lot to do with it. I went from consuming about 3,000 calories a day to 4,200!"
He credits food-delivery service Paleta for delivering his three meals a day plus snacks, and describes what a typical day of eating was like for him.
"Breakfast was usually an omelet with veggies and cashew cheese, a turkey-meat patty, and some fruit; lunch and dinner would be lean protein, veggies, and nuts; snacks consisted of things like snap peas with peanut sauce," he shares. "I don't have the luxury of eating whatever I want whenever I want anyway, because of my type 1 diabetes, so I have been conscientious about food for a long time."
Of course, he also trained hard to gain all that muscle.
"When I was getting in shape for the show, I was doing three sessions a day: one fight-training with Kingdom's coach, Joe 'Daddy' Stephenson, and two strength-building with Gregg [Miele of Heart and Hustle gym]" he reveals. "Each workout focused on a different region of the body -- upper body, core, or legs -- and we'd do a circuit of six different moves for one area. Lifting a lot of weights, really trying to break the muscles down."
Though he now admits that he needs to tone it down.
"I got pretty Hulk-ish," he says. "Now that I'm on tour for my album, I've leaned out about 10 pounds from what I'd gained. It's been fun to change my physicality. My meal plan came down to about 2,500 calories, and the portions got really small. I exercise only three or four times a week."