Funnyman Robin Williams is back in rehab in a bid to maintain his sobriety.

The actor/comedian has checked in to the Hazelden Addiction Treatment Center in Minnesota so he can focus on his long-term sobriety.

The star's representative tells Tmz.com, "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."

Williams has struggled with addiction for decades and last spent a spell in rehab in 2006.