Gaga
Singer Lady Gaga performs during a live concert on ABC's Good Morning America in New York's Central Park Reuters

Lady Gaga has certainly slimmed down during her short pop-music career, but celebrity biographer Ian Halperin says that Gaga is unhealthy and obsessed with weight loss to the point of anorexia.

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, Halperin told Star magazine. 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.

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Lady Gaga is famous for her outrageous and trendsetting fashion, which often includes complex and architectural costumes and wigs. According to Halperin, who is publishing a book on the artist formerly known as Stefani Germanotta, Gaga uses the costumes to hide the effects of Lupus. Gaga has been very open about her battle with Lupus, a disease which attacks the immune system and causes hair loss.

Halperin, who also accused Gaga of having a serious drug problem and consuming substances from heroin to ecstasy, might just be trying to stir up scandal to promote his new book on the pop-music queen. Gaga has admitted that she had a cocaine problem in the past, but claims to have kicked the habit.

In uncertain verb tenses, Halperin told Star that Gaga's friends say that she has done every drug conceivable. You name it she has done it.