GagaChampagneSkinny230.1.jpgIn an interview with Star magazine, writer Ian Halperin is claiming that Lady Gaga, 25, is literally starving herself for her career.

Halperin, who has spent a year researching and writing a tell-all book about the pop star, told the mag:

    "Those who have worked with her on tour reported to me that Gaga barely ate for weeks at a time to fit into her costume. She is sick and obsessed with her weight. One friend told me Gaga will stare at herself in the mirror for hours on end, analyzing and critiquing her body. It's an unhealthy obsession."


In addition, Halperin, who has also written unauthorized biographies of Michael Jackson and Brad Pitt/Angelina Jolie, says Gaga has tried every drug under the sun.

"From heroin to cocaine and ecstasy, her friends say that she has done every drug conceivable," he says. "You name it, she has done it. ... Her drug use started young."

In Gaga's defense, she has never denied that she used to party hard. Mother Monster admitted that in 2005 she was regularly doing cocaine.

Halperin also revealed that Gaga might be using her costumes to hide a secret about her body ... see what he said after the jump.