Actor Allison Mack, 38, was sentenced to 3 years in prison Wednesday after pleading guilty to charges she manipulated women into becoming sex slaves for NXIVM’s leader, Keith Ranier.  NXIVM was a cult group that masqueraded itself as a self-help organization. Mack also received a $20,000 fine.

Mack – best known for her role on the series “Smallville” – appeared in Brooklyn federal court, seeking credit for cooperating against Raniere and taking responsibility for helping him create a secret society of brainwashed women who were branded with his initials. Mack wrote in a letter filed with the court last week that devoting herself to Raniere “was the biggest mistake and greatest regret of my life.  I am sorry to those of you that I brought into NXIVM. I am sorry I ever exposed you to the nefarious and emotionally abusive schemes of a twisted man.”  Mack was once part of the inner circle of Raniere, whose group attracted millionaires and actors among its adherents. Prosecutors said she became a “master” for “slaves” whom she ordered “to perform labor, take nude photographs, and in some cases, to engage in sex acts with Raniere.”

Mack provided information to prosecutors about how Raniere encouraged “the use of demeaning and derogatory language, including racial slurs, to humiliate ‘slaves,’” the government papers said. More importantly, she provided a recording of a conversation she had with Raniere about the branding. Raniere was sentenced last year to 120 years in prison for his conviction on sex-trafficking charges.