Lindsay Lohan has sparked fears she isn't taking her stint in rehab seriously after partying with pal Paris Hilton at a Hollywood club last weekend. The Mean Girls star checked herself into a rehabilitation facility last month but has been spotted out shopping and having lunch with friends. On Friday night, Lohan and Hilton sparked a media frenzy on their way out of Les Deux nightclub. Lohan, who is 20-years-old and not allowed to legally drink in the US, was spotted again less than 24 hours later sneaking out of West Hollywood nightclub Area alone. The star has reportedly angered other residents in her rehab facility who claim she is using the premises more like a hotel than a treatment facility. Lohan's representative Leslie Sloane Zelnik slammed reports she was getting favorable treatment last week saying, "Lindsay is 100 percent not getting special treatment. This isn't the Betty Ford clinic, it's not a lock-down facility. There is personal time."