Former "Smallville" actress Allison Mack pleaded guilty in a Brooklyn federal court Monday to racketeering charges in relation to the cultlike group NXIVM.

Mack entered her plea shortly before jury selection was scheduled to start.

ALLISON MACK IS IN 'ACTIVE PLEA NEGOTIATIONS' TO AVOID TRIAL FOR ALLEGED INVOLVEMENT IN NXIVM SEX CULT

The trial was expected to detail sensational allegations that the group recruited sex slaves for its spiritual leader, Keith Raniere.

Prosecutors accused Mack of helping Raniere recruit women to a secret sub-society within the group.

Mack is best known for her long-running role on the superhero TV show about the early days of Clark Kent’s life. However, it was reported that she was heavily involved in the NXIVM organization shortly after authorities began making arrests. Mack allegedly got involved with the group when she was unhappy with her acting career. She reportedly rose in the ranks to become a key player in its activities, which allegedly included branding its members and finding sex slaves for Raniere.

The defense says the women were never abused.

Authorities say the women were branded by a surgical tool with a symbol that resembled Raniere's initials. Mack has said in an interview that the group emphasized self-discipline and self-empowerment and she likened the branding to getting a tattoo, but cooler.

Mack is said to have been living in upstate New York with alleged cult leader Raniere until he reportedly fled to Mexico in November. She was seen running after him when he was apprehended in Mexico in March.

‘SMALLVILLE STAR ALLISON MACK CITES SCIENTOLOGY AS A DEFENSE IN SEX TRAFFICKING CASE

Two other women charged in the case, former NXIVM executive Nancy Salzman and her daughter, Lauren, have already pleaded guilty.

CLICK HERE TO GET THE FOX NEWS APP

The Associated Press contributed to this report.