The star of the movie Monsters, Inc. and the former television series Roseanne was receiving treatment at the Promises Clinic in Malibu.
Although the reasons for the treatment were not revealed, the actor explained in a press release, "For my family and myself, I voluntarily took the necessary steps to remain sober the rest of my life."
The 55-year-old actor did not indicate how long he received treatment for. His voice can be heard next month in Bee Movie along with Jerry Seinfeld, Renée Zellweger, Matthew Broderick and Chris Rock.