Lady Gaga has never been shy about her cocaine use. She told Vanity Fair in 2010 that her pre-fame period of doing the drug non-stop on the Lower East Side of New York “was a low point. It led to disaster.”

Now, one of her closest confidantes is pulling back the curtain and exposing her coke-fueled days as a struggling artist. Rivington Was Ours: Lady Gaga, The Lower East Side and the Prime of Our Lives, by Gaga’s one-time BFF Brendan Jay Sullivan, paints an unflinching picture of Gaga’s pre-fame life — and just how pervasive cocaine was in it.

In the book, which will hit shelves on August 27, Sullivan remembers hanging with Gaga at her Lower East Side pad and watching her rub a white powder out of her carpet and onto her gums. “It’s mint,” she told him. “I wish it was coke.

“I used to do bags and bags of it. Mostly when I was getting ready to go out, while I was putting on my makeup,” Sullivan says Gaga told him. “I’d get a delivery and then put on some Bowie and treat myself in the mirror. But I only ever did it alone. That was my one rule.”

It was a rule easily broken, the author claims. When hanging with Gaga on another night at rock bar Don Hill’s, she asked him to call a dealer to get a delivery of cocaine.

“I just agreed to score drugs for us both and spend our entire night smoking way too many cigarettes and talking way too fast about ourselves,” he writes. “Then I started to worry. She had a recording session in L.A. the next week. What if it ruined her voice?” But even though the dealer known as “Devil” showed up, Sullivan says he blew him off and the duo stayed drug-free — for that night at least.

On yet another night, Sullivan claims, Gaga tried to get him to score again.

“Did you want to call ‘Judy’?” Sullivan writes that she asked. “Judy is what my friends all cocaine.”

Indeed, most Gaga’s friends were heavy into the drug world while she studied at NYU’s Tish School, according to the book.

Brendan recalls a conversation with Gaga in which she said her NYU friends, “…would buy bags and bags of cocaine. … I’d be out with my friends and you’d catch one of them on the phone with their dads, pretending they needed the money to eat or to buy books or something, and they’d hang up and go to the ATM and take out more money to party.