5:00 PM PT -- London's spokesperson, Dominic Friesen, tells TMZ ... Jeremy's arrest stemmed from a private marital matter with Juliet. We're told it was an isolated incident and "standard protocol in an attempt to diffuse an emotionally-charged situation." The couple's addressing the incident privately.

Jeremy London's been arrested for domestic violence ... and he's looking really rough in his mug shot.

The "Mallrats" actor, and Jason London's twin bro, was booked Friday in Jackson County, Mississippi on one count of domestic violence simple assault -- a misdemeanor. It's unclear right now who else was involved in the alleged incident ... but law enforcement sources tell us he was arrested in the front yard of a home owned by his wife, Juliet London.

As we reported back in the day ... London was charged with domestic violence in 2012 for a fight with his estranged wife, Melissa Cunningham. He allegedly pulled her hair and hit her on the head, but the charges were dismissed a year later.

Jeremy and Melissa divorced in 2014. He's since remarried to Juliet.

Again, we don't know if she's the alleged victim in this latest arrest.