The Lord Of The Rings star was asked by a female follower to persuade Fox, 46, to join Twitter.com in May (12), and he stunned fans when he made the remarks about the actor.
Monaghan refused to back down over the drama - when the fan, named Becca, responded to his comments, writing, "What about all those good times you had together?", Monaghan shot back, "How do you know we ever did? you don't know either of us.he beats women.not isolated incidents.often.not interested."
The comments came just months after a female bus driver, Heather Bormann, launched a legal battle against Fox, claiming he assaulted her while trying to board a party bus in Cleveland, Ohio when she informed him he was not on the private guest list.
She has since dropped her lawsuit, and Fox has spoken out about the dramas, admitting he has had a tough 12 months.
He tells Men's Fitness magazine, "It's been a long, trying year of sitting on my hands on a lot of negative s**t said about me, when they're the furthest things from who I am.
"In the 46 years I've been breathing on this planet, I have never hit a woman before. Never have, never will. I think there's still gonna be a lot of people out there who'll think it's true no matter what.
"The Cleveland situation, the Monaghan situation - was a pile of bulls**t, and I'm not gonna waste too much breath on that."