Robin Williams in alcohol rehab

Williams has previously suffered drink and drug problems

Oscar-winning actor and comedian Robin Williams is in rehab for alcoholism, his publicist has said.

In a statement Mara Buxbaum said Williams had been sober for 20 years, but had "found himself drinking again".

He "has decided to take proactive measures to deal with this for his own wellbeing and the wellbeing of his family", Ms Buxbaum said.

Williams, 55, won an Oscar for his supporting role in the 1997 film Good Will Hunting.

He stars in Man of the Year, due for US release in October, and voices an animated penguin in Happy Feet, set to reach cinemas in November.

"He looks forward to returning to work this fall to support his upcoming film releases," Ms Buxbaum said.