Robin Williams is in a Minnesota rehab facility "to fine-tune and focus on his continued commitment, of which he remains extremely proud," according to a representative.
Williams has of late been working on a series of "back-to-back projects".
According to TMZ, the actor and comedian has checked into the Hazelden Addiction Treatment Center in Minnesota.
The 62-year-old star is reportedly participating in a programme which immerses the client in the Twelve Step design for living "that can inform and transform every aspect of your life," according to the facility's website.
Williams had been sober for 20 years, before relapsing while filming the 2005 film, The Big White. His family persuaded him to enter rehab one year later, and he has remained sober since.
In 2010, Williams talked to USA Today about his 2006 time in rehab. "I got help when I realised I was just destroying everything," he said.
He added: "When you're having blackouts on a regular basis... Blackouts, I joke, are like sleepwalking with activities. But those are really frightening, where you wake up and you have to have people [tell you what you did]. And then you go: 'This is scary'."
