Nick Jonas is inspiring major fitness goals.

The 24-year-old star has grown up before his fans' very eyes, and in the December issue of Men's Fitness, he reveals how he went from a "teen idol" to getting "leading man ripped."

On the cover of the magazine, Jonas flashes his impressive six-pack abs while giving a sultry stare. The image is reminiscent of the crotch-grabbing photo he posed for in Flare magazine back in 2014.

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"The way I work out is really placing trust in the people around me," Jonas says in a behind-the-scenes look at his Men's Fitness photo shoot. "I've got a couple good trainers that keep all of my workouts in order."

The "Close" singer says he tries to be healthy because he loves "being fit," but he's also a Type 1 diabetic. Jonas admits in his interview with Men's Fitness's Mickey Rapkin that at age 13, he had "wild mood swings," because he wasn't managing his health condition properly. He now wears a Dexcom Continuous Glucose Monitor, which monitors his blood sugar.

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"When I’m on the road, I always make healthy choices," he notes. "I don’t have a meal plan delivered to me, but I know what not to eat. I’m always cautious about the food I put in my body."

Being a Type-1 diabetic can be risky for Jonas when he's doing hardcore strength training to prepare for his role as a boxer in Direct TV's Kingdom. "We always keep glucose in the gym,” Gregg Miele, the owner of a private gym in Los Angeles, explains. “We’re always prepared for that. And as for diet, we got his blood work done and put him on a specific blood-type diet to make sure he wasn’t eating any inflammatory foods that would hinder his goals or set us back.”

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"You just feel better when you put nutrition into your daily life," Jonas touts in the behind-the-scenes footage from his photo shoot. "It's a whole process."

Jonas admitted to ET that there was a time in his life where he thought his diabetes could kill him. "When I was first diagnosed, I didn't really know a lot about the disease, so I was actually thinking I was going to die," he disclosed, adding that he has learned how to "deal with it."