Pete Doherty has said that the director of his debut film tolerated the former Libertines frontman's heroin use.
'Confession of a Child of the Century' was shot in France and featuring the singer as a 19th century vagabond.
Doherty was urged to go to rehab before shooting, but says he was "so absorbed in the work, there wasn't a chance.
"I couldn't hide it from [director Sylvie Verheyde]. She didn't really care. It was just a question of how quickly I can find a vein and then let's get on with it."
He added to The Guardian newspaper: "It's poison but it's also medicine. When you're in that state, you can't function unless you have your fix."
He also admitted that his drinking caused "a few problems" on the set.
He said: "I wasn't going to drink coloured water. If I am doing a drunken scene, I am doing a drunken scene. That did cause a few problems. Once I start drinking, I have to carry on."
The singer also suffers from crippling stagefright, which he says affects his abilities to perform, but also admits his current band, Babyshambles, have a far from professional outlook.
He said: "If the Libertines were three reliable, talented musicians and one f**k-up, Babyshambles is like one talented musician … and the rest of us are f***ed up."