Tom Arnold Divorce -- Back On (For Realsies)

Tom Arnold is officially pulling the plug on his third marriage -- again.

TMZ obtained divorce papers filed yesterday in Los Angeles County Superior Court, in which Arnold blames his split with political consultant Shelby Roos on irreconcilable differences.

The couple, who married in 2002, split briefly in August 2006 after Arnold filed a petition for legal separation. Six months later, Tom asked a judge to dismiss that request while the couple attempted to work things out.

The couple has no children. This will be Arnold's third divorce.