The 'American Idol' host – who suffered mild kidney failure earlier this year, and was hospitalized with blood clots on his lungs last month – has changed his lifestyle because he is "scared" of dying and leaving behind his wife Mariah Carey and their 10-month-old twins Moroccan and Monroe.

Nick – who has been married to the singer since 2008 - said: “I want to be there for my children. You want to make sure you’re alive more than anything. I’m having a good time, though.

"It’s scary when you think about your health — where it can go — but when you’re doing it for the right reasons, and I’ve overcome so much in the past few months, it’s good.”

But the 31-year-old star initially thought doctors were "joking" when they warned him he might die if he did not slow down.

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He added to America's OK! magazine: "I thought it was them over-exaggerating. [I was,] like, ‘Yeah, right.’ And then, when I had a couple more scares and things got serious, I was, like, ‘Okay, this isn’t a joke. I’ve got to change the way I’m living my life.’ ”

Since being warned about his health, Nick quit his drive-time radio show on 92.3 NOW FM "under doctor's orders" last month, and he is now being "nursed" back to health by Mariah.

He explained: “She’s always taking care of me. She’s my nurse. She makes sure I take all my medications, makes sure I eat. It’s great!”

Despite his health concerns, Nick plans to continue presenting 'America's Got Talent' - which is set to start filming again this summer in New York City - because he believes it's "going to be the biggest show in the world."