Robin Williams is back in rehab - but only to make sure he keeps up his good work at staying sober.

The actor and funnyman, 62, checked himself into the Hazelden Addiction Treatment Centre in Minnesota, where he will be spending several weeks, according to TMZ.

But his representative told the site that the Mrs Doubtfire star - who battled addiction for decades - had not fallen off the wagon.

They told TMZ: "After working back-to-back projects, Robin is simply taking the opportunity to fine-tune and focus on his continued commitment, of which he remains extremely proud."

The Mork And Mindy star is staying at The Lodge, a part of Hazelden which is known for helping patients maintain long-term sobriety.

The actor fell off the wagon in 2006 after 20 years of sobriety and checked into Oregon's Hazelden Centre for treatment.

His rep said at the time: "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.'

He previously battled an addiction with cocaine.

This year has been a busy one for the Oscar-winning actor.

The Good Will Hunting star has appeared in The Angriest Man In Brooklyn with Mila Kunis as well as Boulevard with Kathy Baker.

He's also been filming Merry Friggin' Christmas, Night At The Museum: Secret Of The Tomb and recording a voice role for Absolutely Anything.

He also starred in The Crazy Ones TV series, with Sarah Michelle Gellar.