My exclusive snaps show the sozzled singer leaving an awards party with traces of snow-white powder coating her nostrils.
It looks like the â€˜party' drug cocaine â€” if so, I'm afraid Amy has hit a grim low.
A passer-by said: "It was late and Amy was totally off her face, but somehow she still had loads of energy.
"She was jiggling around and whistling to herself. When she got in the cab she started wiping her nose furiously." Amy had been celebrating a huge night at the Brits, where she picked up a gong for Best Female.
Afterwards, she was whisked to the Brits aftershow bash at London's trendy Mocoto.
At 1.30am, the party animal was then seen heading to NOEL and LIAM GALLAGHER's private party in The Cuckoo Club.
My clubbing spies tell me she STILL had a spring in her step an hour later when she returned to Mocoto.
Last night a close friend of Amy's told me: "Everyone knows Amy's one of the biggest caners on the scene at the moment, but if she's getting into Class-As, it's bad news."
The 23-year-old soul divaâ€”whose most successful song is called, er, Rehabâ€”has previously admitted to binge drinking and smoking cannabis.
She said last year: "I was doing a few drugs but only dabbling. Cocaine isn't really my thing."
She also revealed her drug habit played havoc with her eating, leading to dramatic weight loss. "I'd get up, smoke two big spliffs then have a fry-up. It's all I'd eat all day," she said. After her success at the Brits, Amy faces growing pressure to try to better her superb No1 album, Back To Black. But it's feared work demands may awaken her old demons.
Despite all this, her dad Mitch reckons cocaine abuse is not a concern. He said: "I don't worry about it because she's told me she doesn't take it."
But her concerned friend said: "Amy loves the line in Rehab where she sings, â€˜They tried to make me go to rehab, but I said no, no, no.'
"Now we just hope she decides to change her tuneâ€”for her own sake."
I'm not too bothered about it. Cocaine is the rich man's drug and so many celebs do it. I just hope Amy doesn't go off the rails.