The rock band, which consists of vocalist Reynolds, lead guitarist Wayne Sermon, bassist Ben MCKee and drummer Daniel Platzman, rose to fame with songs It’s Time and Radioactive from their debut 2012 album Night Visions.

Reynolds has now revealed that right as the band was on the cusp of finding stardom in 2008, he was struggling with his health.

"It was beyond the pain that you feel when it’s just a back ache. It felt like someone was drilling my nerves," he told "It was right when the band was starting to have minor success - we were starting to sell out small clubs, and we were playing these very active shows and it started to make me have to cancel shows."

During this time Reynolds shares that he couldn’t get on stage, sleep or sit down for more than half an hour. After suffering from "debilitating" pain that forced him to cancel shows, he eventually consulted with a rheumatologist who diagnosed him with ankylosing spondylitis (AS), a type of arthritis in which there is long term inflammation of the joints of the spine.

"I went, and then they did the test to see if it’s in your genes - which it was, because it’s an autoimmune disease," he explained. "And then they diagnosed me and put me on a treatment plan, which fixed me almost immediately."

The Las Vegas native now controls his symptoms by staying active, doing yoga and following a healthy diet. While he initially hesitated about sharing his diagnosis with Imagine Dragons’ fans, the 29-year-old hopes to be able to help others in a similar situation by participating in This AS Life Live! an online show for people with AS.

"I have a chance to really raise awareness and help people that are just becoming diagnosed to see that there’s actually light at the end of the tunnel," Reynolds said.

Imagine Dragons are currently working on their third album, which will likely be released next year (17).