The 'I Believe in a Thing Called Love' rocker admits his substance abuse made him paranoid and irresponsible, and he knew his lifestyle had gotten out of control when he woke up in mid-air dressed as a microphone and soaked in his own urine.
In an interview with The Sun newspaper, he said: "I woke up in first class on a plane wearing a microphone fancy dress costume and realised to my shame that I had publicly wet myself. It was not my finest hour.
"It was during a ridiculous phase of not trusting airline food. I began to think they were putting chemicals in it to make you constipated. So I decided I wouldn't eat anything and just drank until I passed out."
Justin, 36, has compared his behaviour to that of an animal, claiming he had essentially become a chimpanzee.
He added: "I was smashed up all the time. It was getting to the stage where I was literally behaving like a chimpanzee. I might as well have been clambering up on stage, s***ting in my hand and eating it."
Justin quit The Darkness in 2006 and entered rehab where he quit drink, drugs and smoking, and he now prefers to channel his energies into adding to his extensive collection of tattoos.
He said: "I think most of my obsessiveness has transferred to ink. I've lost count of how many tattoos I've got, but I'm covered in them - mostly musical instruments I admire."
The Darkness played their first large scale comeback show on Friday (10.06.11) at the Download Festival at Donington Park in the UK.