Teddy Joye Hicks Gibson - who married the actor`s father Hutton Gibson in 2001 - claims Mel is responsible for their break-up after her spouse filed for divorce and kicked her out of their home in June.
According to gossip website TMZ, Teddy, 78, is suing Mel for $65,000 to cover the legal bills from both her divorce and a court order forcing him to let her into the marital home.
Earlier this month she filed for a restraining order against Mel, alleging the `Braveheart` star had threatened her and tried to sabotage her marriage.
In legal documents, Teddy said Mel and his sister Maura have a grudge against her because she doesn`t approve of controversial medical treatments they have been urging her husband to undergo for his various illnesses, and she alleged they manipulated their ailing father into filing for a divorce, something she insists her devout-Catholic spouse wouldn`t usually agree to.
She also claimed 93-year-old Hutton recently penned her a love note saying: "Our mutual love is permanent."