Last month, the 54-year-old actor faced claims - made by Cathriona's estranged husband Mark Burton - that he supplied his ex-girlfriend with drugs so that she could take her own life, resulting in her tragic suicide last year.
Now, Cathriona's mother Brigid Sweetman has filed a second lawsuit against the 'Bruce Almighty' actor, claiming that her daughter took her own life after she realised the star had given her three sexually transmitted diseases.
But it doesn't stop there, as according to TMZ Brigid also claims that Jim shamed Cathriona by calling her a "w***e", and threatened her into keeping silent.
The lawsuit states that in 2013, Cathriona learned from her doctor that she had contracted two different types of herpes, as well as chlamydia. Brigid says the actor was at first dismissive of the claims, and later argued that she could have contracted the diseases from someone else.
The suit claims that Cathriona struggled emotionally before she overdosed on Ambien, Propranolol, and Percocet.
However, TMZ also report Marty Singer - the lawyer for the 'Dumb and Dumber' star - has branded the lawsuit as "a sham", as he claims Cathriona and her mother have been estranged for years.
Marty also claims that Cathriona was forced to move out of her home when she was 15, due to the way her mother treated her.
Jim's lawyer states that Brigid is directing her grief and anger over the loss of her daughter toward the star, but branded her actions as another attempt to capitalise on her death.