The 47-year-old singer ' who has a history of substance abuse issues ' voluntarily entered an out-patient rehab program around 10 days ago, her spokesperson has confirmed.

The representative told People.com: "Whitney Houston is currently in an out-patient rehab program for drug and alcohol treatment.

'Whitney voluntarily entered the program to support her long-standing recovery process."
Angela Bassett revealed earlier today (09.05.11) that she and Whitney ' who hasn't appeared in a film since 'The Preacher's Wife' in 1996 - are to work together again on a sequel to 1995 movie 'Waiting To Exhale' and it is believed the singer sought treatment prior to relaunching her big screen career.

A source told website TMZ: "She's cleansing herself to get ready for a new movie."

According to the website, the treatment program allows Whitney ' who was pictured at a Prince concert last weekend ' to go out in public as long as she has a monitor.

In 2009, Whitney confessed to being a cocaine addict herself in TV interview with Oprah Winfrey and admitted her and her ex-husband Bobby Brown's drug use spiraled out of control after she starred in hit movie 'The Bodyguard' in 1992.

She said: "Me and Bobby were lacing our marijuana with base. We would buy a kilo. We were not pipe smoking.

"You roll it up and you smoke it in your weed. It's almost like heroin cocaine speedballs but you level it off with marijuana."

Earlier this year, Whitney and Bobby's daughter Bobbi Kristina, 18, was accused of being a cocaine addict by a former boyfriend but denied his claims.