Ben showed up at his Pacific Palisades home after driving from his live-in rehab facility in Malibu. Sources with direct knowledge tell TMZ, Ben has permission to leave to work out at his home. One of the conditions ... he travels with his sober coach.

We're told Ben has been allowed to leave before for the same purpose and it's now part of his rehab regime.

TMZ broke the story ... Jennifer Garner staged an intervention last month and drove Ben to rehab. We're told Ben actually wanted the help because he was in a deep tailspin after falling off the wagon.

The tipping point came 2 days before the intervention, when Jen saw a pic of Ben accepting delivery of beer and hard liquor at his home.

As we reported, Ben had been on and off the bottle for 18 month and that's one of the reasons his divorce case had stalled. We're told Jennifer did not want to cement joint custody into their deal until she knew he was stable. We know Ben and Jen have settled their divorce, and the plan is to finalize with the judge when Ben leaves rehab.