Troubled starlet Lindsay Lohan cut a lonely figure during her second day at the Promises rehab facility in Malibu.

Wearing dark red-framed glasses, skinny black jeans and zip-up jacket, the 20-year-old was photographed wandering around the centre on her own.

Meanwhile, her estranged father Michael Lohan has made claims that the Mean Girls star suffers a number of addictions including alcohol and the painkiller OxyContin, according to reports.

The drug, also know as Oxycodone, is regularly referred to in parts of America as 'hillbilly heroin' and has been linked to scores of deaths in the US.

Lindsay Lohan wandered around the grounds of the rehab centre alone

Michael, who recently served jail time for assault and driving while intoxicated, told E! Online: "I spoke to the people treating Lindsay, because I wanted to make sure she was getting the right care. And I'm satisfied they are doing the right thing for her, helping her detox from the painkillers and things. That's a very important step."

Lindsay publicist Leslie Sloane Zelnik has not yet responed to the claims.

Lindsay faces weeks, potentially months, of treatment at the clinic - it is the same centre that Britney Spears checked into earlier this year.