The Lost star had attempted to board the coach in Cleveland in the early hours of 28 August (11) when he was confronted by driver Heather Bormann because his name was not on the private guestlist.
A scuffle ensued, resulting in Bormann punching Fox in the face, leaving him ""spitting blood"".
According to court documents filed in Ohio, Bormann claims Fox came at her ""with his fists, delivering sudden and severe blows to her right breast, groin, arm and legs, inflicting severe, disabling injury"".
She alleges she ""instinctively defended herself"" and hit out at the actor, injuring her hand and fingers in the process, reports TMZ.com.
Fox, who was in Cleveland filming new movie I, Alex Cross, was detained by police after the altercation, but was not formally arrested. Bormann subsequently filed charges against the actor and cops are currently investigating the incident.
However, the 45-year-old star is now facing more legal trouble - Bormann is suing for more than $25,000 (£15,625) for assault, battery and intentional infliction of emotional distress.