AceShowbiz -

She won't be around the town anytime soon. Lindsay Lohan will instead stay in rehab until an undisclosed time. The troubled pop star has decided to remain in rehab until she fully recovers from her addiction.

"She is staying in Promises for longer than a month. We don't know how much longer because of her work schedule, but she is taking rehab very seriously this time and not messing around," a friend of Lindsay tells the New York Post newspaper.

Lindsay checked into the Promises treatment center in Malibu, the luxury facility where pop star Britney Spears was recently a patient, on May 28th following a DUI arrest the days before. "Lindsay admitted herself to an intensive medical rehabilitation facility on Memorial Day. Because this is a medical matter, it is our hope that the press will appreciate the seriousness of the situation and respect the privacy of Lindsay as well as the other patients receiving treatment at the facility," her representative said at that time.

Due to her extended rehab stay, Lindsay who initially set to leave Promises at the end of this week has on Monday June 18th canceled her 21st birthday party at Las Vegas' PURE nightclub, released a statement through her representative saying, "The party was cancelled officially over two weeks ago. Lindsay will not be having the birthday party at Pure and is focusing on her recovery 100 per cent."