The This Love singer was rushed to hospital after lacerating his chest when a workout went awry.
He tells US magazine Blender, "It was one of the most painful things I've ever experienced.
"It was really an embarrassing story, but I might as well tell it - I was working out backstage with the kind of cable pulleys that you put onto a doorstop.
"James Valentine, our guitar player, opened the door and basically this really thick rubber cable with a metal carabineer on the end of it snapped with the force of what seemed like a bullet, and hit me right in the middle of my chest.
"It could have killed me. It lacerated my chest right down the middle, and I had to go to the hospital.
"I did perform that night, though. They pumped me full of drugs, and I was so high that I actually wanted to play."
Source: WENN