India Oxenberg claims she was branded with the initials of the organisation's jailed founder, Keith Raniere, before becoming his slave - and she has singled out former "Smallville" star Mack as the woman who brought her into the cult.
"It was an abusive dynamic just by the sheer fact that she had control over me," India tells "Good Morning America". "She did it strategically. She knew that I was at a vulnerable place in my life and I was desperate for something, and she targeted me for that."
Oxenberg opens up about her time with the cult in new Starz documentary, "Seduced: Inside the NXIUM Cult", revealing she had to run everything she did past Mack - even what she ate. "Allison said I could only eat 500 calories or less each day and then before eating anything I had to ask permission, so 'Master, may I please have 90 calories?,' " she explains. "It was supposed to be a practice in discipline and self-restraint."
Eventually, she was told she needed to become a "master" just like Mack. "I was told I needed to recruit," she adds. "I was not a good master. I didn't want to control this person, I didn't want to boss them around, tell them what to do, scare them."
While she was living with Mack in Brooklyn, New York, India's mother discovered her daughter was part of the cult and told her to get out and seek legal help before she was arrested as lawmakers descended on the cult's leaders.
India quickly found herself on the side of the prosecutors after she found a flashdrive featuring incriminating evidence against Raniere and handed it over to prosecutors.
Mack and Raniere's representatives have yet to comment on India's remarks or the new documentary.
The convicted cult svengali and the actress, who pleaded guilty to racketeering and conspiracy charges, are still waiting to hear how long they'll spend behind bars. Raniere, 60, was found guilty of charges including racketeering and sex-trafficking last year (19). He faces up to life in prison when sentenced later this month (Oct20).
Meanwhile, Seagram's heiress Clare Bronfman was sentenced to serve more than six years behind bars for her links to the Nxivm cult at the end of last month.
The daughter of late Canadian billionaire Edgar Bronfman, Sr. pleaded guilty to charges of conspiracy to conceal and harbour an illegal alien for financial gain and fraudulent use of identification in 2019. Bronfman, who brought women into the country illegally and helped fund the cult, became the first person to be sentenced in the case.