Nick Wass / Invision/AP 1 / 8
Nick Wass / Invision/AP 1 / 8

NEW YORK (AP) -- Whitney Houston is back in rehab.

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A representative for the superstar singer confirmed Monday that Houston is undergoing treatment. Kristen Foster says Houston is in an out-patient program for drug and alcohol treatment.

She says it is a voluntary measure and part of Houston's "long-standing" recovery process.

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The 47-year-old has battled drug abuse in the past. She released a comeback album in 2009, but her 2010 tour was troubled: Houston canceled some dates due to illness and received negative reviews from fans who were disappointed in the quality of her voice and performance.

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