Just as jury selection was set to begin in the NXIVM case, former actress Allison Mack pleaded guilty to charges for her role in the alleged cult, following days of plea negotiations with the government.

Mack entered a guilty plea to racketeering charges. Mack was initially listed for Monday morning on the court schedule in Brooklyn, for jury selection, but was later removed and rescheduled for “criminal cause for plea.”

The "Smallville" actress was also facing charges of forced labor conspiracy, wire fraud conspiracy, sex trafficking, sex trafficking conspiracy and attempted sex trafficking. The status of those charges are unclear. 

Mack’s move makes her the third person in the NXIVM case to plead guilty. Lauren Salzman admitted to two counts — racketeering conspiracy and racketeering. Her mother, NXIVM co-founder Nancy Salzman, admitted to a racketeering conspiracy charge. Lauren had also been charged with forced labor conspiracy and wire fraud conspiracy. The status of those charges is still unclear.

That leaves NXIVM co-founder Keith Raniere, Seagram's heiress Clare Bronfman and NXIVM bookkeeper Kathy Russell facing trial. Russell has also been engaged in plea negotiations.

Court papers allege NXIVM formed a secret society of women who were branded with Raniere's initials and forced to have sex with him.

The trial for any remaining defendants is scheduled to begin on April 29.

The Associated Press contributed to this report.