“Dynasty” actress Catherine Oxenberg slammed Nxivm sex-cult leader Keith Raniere as a “monster” and “typical sociopath” for calling his accusers liars at his sentencing in Brooklyn federal court on Tuesday.

Earlier in the day, Oxenberg’s 29-year-old daughter India wept as she told the court that the sick sex-trafficking Svengali raped and starved her.

But when it came time for Raniere, 60, to address the judge, the convicted sex trafficker shamelessly labeled his accusers as liars.

Catherine, who is also the daughter of Princess Elizabeth of Yugoslavia, wasn’t having it.

“Only a monster would discredit his victims..,” she wrote on Twitter. “Remorseful for what? himself?”

“Typical sociopath.”

She also tweeted her thanks to the federal prosecutors in Brooklyn who brought Raniere to justice.

“U saved my daughter India and countless others, I am forever grateful. TY for putting this predator behind bars,” she wrote.

The actress, 59, waged a years-long campaign to get India out of Nxivm and bring Raniere to the attention of authorities after learning her daughter was part of a secret master-slave group where she was branded with the guru’s initials.

She penned a book about the ordeal, and her crusade was also captured in two recent TV docuseries — HBO’s “The Vow” and Starz’s “Seduced.