Most parents think their children’s violent mood swings and pizza cravings are down to puberty, but when Nick Jonas started showing these symptoms, his family immediately sensed something was wrong.
 
The youngest of the Jonas Brothers was usually a happy child, but when the 15-year-old became sullen and distant, his parents decided 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."

Nick has launched a campaign – in partnership with Bayer Diabetes Care -  aimed at encouraging young people to be proactive when it comes to managing their diabetes.

See the youngest Jonas Brother looking all grown up at the press conference yesterday.