Mrs. Doubtfire 12 steps herself into rehab.

People reports:

Robin Williams is seeking treatment for alcoholism, his publicist said Wednesday. "After 20 years of sobriety,

Robin Williams found himself drinking again and has decided to take proactive measures to deal with this for his own well-being and the well-being of his family," the actor's rep, Mara Buxbaum, said in a statement. "He asks that you respect his and his family's privacy during this time," the statement continues. "He looks forward to returning to work this fall to support his upcoming film releases."

Williams, 55, is currently starring in the thriller The Night Listener and will appear in the drama August Rush and the comedy Man of the Year, both due later this year.

The comic has battled substance abuse before. During his swift rise to fame on the 1978-1982 sitcom Mork and Mindy, Williams became addicted to alcohol and cocaine, he has admitted. "Cocaine for me," Williams told PEOPLE in 1988, "was a place to hide. Most people get hyper on coke. It slowed me down. Sometimes it made me paranoid and impotent, but mostly it just made me withdrawn. And I was so crazy back then – working all day, partying most of the night – I needed an excuse not to talk. I needed quiet times and I used coke to get them."

Six months before his son Zachary was born in 1983, Williams quit cocaine and alcohol – cold turkey. "No visit to the Betty Ford Center, no therapeutic support," a friend told PEOPLE in 1988. "He just quit, and he hasn't touched drugs or drink since."

What made him quit? Two events: His first wife, Valerie, became pregnant with Zach and pal John Belushi died from a drug overdose just a few hours after Williams snorted a line of coke with him at a hotel. "The Belushi tragedy was frightening,''

Williams, who is also dad to daughter Zelda, 17, and son Cody, 14, with second wife Marsha, told PEOPLE. "His death scared a whole group of show business people. It caused a big exodus from drugs. And for me there was the baby coming. I knew I couldn't be a father and live that sort of life."