Nick Jonas, the youngest brother of The Jonas Brothers, has pulses racing with a new sexy-selfie he posted to his Instagram account, People magazine reports.

The 20-year-old musician showed off his flat abs and chiseled physique in a "post-workout" picture. He captioned the photo: "I never do this but... Healthy Living and fitness update," he wrote. "#diabeticinshape #2.0"

In the rare semi-nude glimpse of the singer he gave fans a sneak peek of what he looks like after just hitting the gym. Many fans commented on the picture telling Jonas that they were glad he was healthy and looking good after being diagnosed with diabetes in November 2005.

The younger brother told Diabeteshealth.com, that before he was diagnosed with the illness he was experiencing many of the symptoms associated with it but wasn't sure what was going.  

"I had a terrible attitude, which was totally odd for me because I'm actually a nice person," he told Diabetes Health. "Especially being on the road around people all the time, you have to keep that positive energy going. And it was hard."

He said within the first two and three weeks of being diagnosed he lost about 15 pounds. He kept the diagnosis to himself until 2007 when he publicly announced that he had diabetes at Carnival For a Cure. He said he always knew he wanted to go public with the news but was waiting for the right to do so.

"I found it amazing just how many people know somebody with diabetes or have diabetes themselves," he said. "We'd get these stories about how some of the kids were really afraid to tell their friends and how my situation gave them courage to do that. The fact that I'm able to have somewhat of a spotlight to share my story, I just feel blessed."

Earlier in the month The Jonas Brothers invited a young fan living with diabetes to their concert at the W Hotel in Boston, Patch reports. The concert, hosted by Kiss 108's Matty in The Morning show, was an acoustic concert dedicated to the radio stations listeners and five patients from Joslin Diabetes Centers.