Jim Carrey is counter-suing his late girlfriend's mother and husband for extortion.

The 55-year-old actor has been accused by Cathriona White's mother Brigid Sweetman and estranged husband Mark Burton of giving his girlfriend three sexually-transmitted diseases and providing the drugs used by the make-up artist when she took her own life in September 2015.

However, Jim insists they are trying to extort him and after he issued a counter-suit, he wrote on Twitter: ''There's a lot of news coming out today. This is my statement on the matter.''

He included a note, which read: ''Today I filed a cross-complaint against Filippo Marchino, The X-Law Group, Mark Burton and Brigid Sweetman. Unfortunately, I made the mistake three years ago of giving in and settling false claims made against me by Mr. Marchino, on behalf of Cat, as mounting a public defense is a very costly and painful process. At the time I felt Cat was being exploited by Marchino.

''Since this new case was filed, I have discovered the depth of deception behind those false claims, the kind of deception decent people fall for, because to us, such behavior is unimaginable. I will not give in a second time to these same fraudulent charges initiated by Cat's husband in name but not substance Mark Burton, and her estranged mother. Nor am I responsible for what these desperate characters have inadvertently unearthed about the woman I adored. I was clearly blinded by my affection. Regardless, I will hold a place of empathy, and forgiveness for Cat and continue to focus on the many blessings in this life (sic).''

In his filing, Jim claimed that between March and August 2013, Cathriona, with her lawyer Marchino's help, threatened to ''go to the press'' with false claims that he had given her STDs unless he paid her ''millions of dollars.''

The suit added: ''In this case, Cross-Defendant Filippo Marchino took what started as a warm and exciting romance between Jim Carrey and Cat White, a beautiful yet immature and emotionally damaged woman, and turned it into an act of extortion, coercion, and theft. Rather than engage in a protracted and expensive public battle, Jim, as many in his position do, succumbed to the demands and privately resolved the issue with Cat and her lawyer.

''In the heartache and grief that followed her tragic loss, Cross-Defendants Filippo Marchino, The X-Law Group, Mark Burton, and Brigid Sweetman filed the underlying complaint hoping to profit a second time from the same false and fraudulent claims made and resolved two years earlier.''

He is seeking unspecified damages.

However, Michael Avenatti, attorney for Burton and Sweetman, hit back at Jim, saying: ''Jim Carrey is so desperate to avoid the public knowing the truth about his own outrageous conduct, that he has now resorted to outlandish accusations against innocent people. As his red-carpet interview from a few weeks ago shows, the guy is incoherent and unhinged. He needs help.''