Teen pop star Nick Jonas and his family sensed he was battling a health problem, because he started suffering violent mood swings.
The normally happy 15-year-old became sullen and distant, prompting his parents to seek advice from a doctor, who ran a series of tests before diagnosing him with diabetes.
Nick's mum Denise explains, "Nick was an especially wonderful child. So when he started acting with a bad attitude, I knew something was wrong."
And Nick reveals another side effect of the illness - food cravings.
He tells WENN, "With diabetes you'll get these weird cravings out of nowhere. While on tour, I started craving Pizza Hut. That was it, that was all I needed. I'm usually pretty flexible when it comes to food choice, but this time I was really stubborn that I had to have pizza hut and I made them pull the tour bus over."