Whitney Houston voluntarily enters rehab

Whitney Houston is back in rehab.

A representative for the singer confirmed on Monday that Houston is undergoing treatment. Kristen Foster says Houston is in an out-patient programme for drug and alcohol treatment. She says it is a voluntary measure and part of Houston's "long-standing" recovery process.

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 cancelled some dates due to illness and received negative reviews from fans who were disappointed in the quality of her voice and performance.