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Pop singer Whitney Houston back in rehab

Singer Whitney Houston, performs with Dionne Warwick at the pre-Grammy gala & salute to industry icons with Clive Davis honoring David Geffen, Sunday, Feb. 13, 2011, in Beverly Hills, Calif. (AP Photo/Mark J. Terrill)

May 9, 2011 12:00:00 AM PDT
Whitney Houston is back in rehab.

A representative for the singer has confirmed that Houston is in an out-patient program for drug and alcohol treatment.

Houston's rep said the singer entered treatment voluntarily. The 47-year-old, one of the most successful singers in pop music history, has battled problems with drug addiction for years. But in 2009, as she released a comeback album, she declared herself healthy and clean.

However, her 2010 tour overseas 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.

It is unclear how long Houston will be in rehab or where she's being treated. However, Houston has been visible recently. Last week, she sang on stage with Chaka Khan during Prince's concert in Los Angeles.

The Associated Press contributed to this story