Actress Allison Mack, who is best known for her role on the TV series “Smallville,” has pleaded guilty in a sex-trafficking case.

Deadline reported Mack, 36, initially entered a plea of not guilty on racketeering charges of sex trafficking, sex trafficking conspiracy and forced labor conspiracy. She was indicted on those charges last year. The New York Times reported on Monday she had pleaded guilty to racketeering and racketeering conspiracy charges.

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According to court documents, a cult-like group called NXIVM, led by founder Keith Raniere, formed a secret society of women who were branded with Raniere's initials and forced to have sex with him.

The Associated Press reported that Mack cried as she entered her plea in federal court in New York.

“I have come to the conclusion that I must take full responsibility for my conduct, and that’s why I am pleading guilty today,” she said, adding, “I believed Keith Raniere’s intentions were to help people, and I was wrong.”

Related: 'Smallville' actress Allison Mack indicted for alleged role in sex trafficking case

Mack also apologized to the alleged victims.

"I'm very sorry for the victims of this case," Mack said, according to Vulture. "I'm very sorry for who I've hurt through my misguided adherence to Keith Raniere's teachings.

“I know that I am and will be a better person because of this.”

Mack faces up to 20 years in federal prison if convicted, Vulture reported. Her sentencing has been scheduled for April 29, The AP reported.