Lindsay Lohan has promised to turn her life around in 2011.

The 'Mean Girls' actress is set to complete three-month court-ordered treatment at the Betty Ford Clinic tomorrow (03.01.11) and she is keen to start the new year on a positive note.

Writing on her twitter account on New year's day (01.01.11), Lindsay said: "Today is the first day of the rest of my life. 'The future depends on what we do in the present.' - Mahatma Gandhi... One step at a time.... (sic)"

Lindsay's promise comes after her mother Dina revealed she has managed to stay drug and alcohol free since entering the facility in October.

She said: "She's amazing. She's been in Betty Ford and it's life-changing. She's not on anything. She didn't go through any withdrawals when she was incarcerated. She's even stopped smoking."

The 24-year-old star was told to enter rehab after breaching the conditions of probation set for a 2007 conviction for driving under The Influence.