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 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.