Robin Williams has checked himself into another rehab facility, in hopes that it will help him reach his goal to maintain long-term sobriety.

Williams’ reps told TMZ today that the actor will be staying at Hazelden Addiction Treatment Center near Lindstrom, Minnesota for several weeks. His people have assured fans that Williams has not fallen off the wagon, stating:

“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.”

“This is not about him falling off the wagon,” a source told FOX411. “It’s like an educational and spiritual facility… It’s all very healthy.”

Williams has struggled with an addiction to cocaine and alcohol for decades. He quit both cold turkey in the early 1980s, after his friend John Belushi overdosed in 1982. He then stayed sober for 20 years, before falling off the wagon in 2006. He checked into rehab for the first time that year.

“It’s hard admitting it, then once you’ve done that, it’s real easy,” Williams once told Good Morning America. “You think people don’t notice. Then you find out later, ‘We knew. … You went outside naked.’ No, I didn’t. But even the dog was like, ‘What’s wrong, boy?’ Humiliation gives you humility.”