NEW YORK >> A television actress best known for playing a young Superman’s close friend was charged with sex trafficking, after federal prosecutors said she worked as a slave “master,” recruiting unsuspecting women to a cult-like group led by a man who sold himself as a self-improvement guru.

Allison Mack was accused in an indictment unsealed today in federal court in Brooklyn. She was scheduled to appear in court later in the day.

Mack, 35, starred in The CW network’s “Smallville,” ending in 2015, but has played only minor roles since then. Prosecutors said she helped recruit women for leader Keith Raniere and his cult-like organization called NXIVM. She told the women they were joining what was purported to be a female mentorship group, prosecutors said.

But “the victims were then exploited, both sexually and for their labor,” according to federal prosecutors.

“Mack and other … masters recruited … slaves by telling them that they were joining a women-only organization that would empower them and eradicate purported weaknesses the NVIVM curriculum taught were common in women,” prosecutors said.

Prosecutors said she required women she recruited to engage in sexual activity with Raniere, who paid Mack in return.

Raniere, 57, was arrested last month in Mexico, brought to the U.S. on March 26 and is being held without bail in Brooklyn.

The FBI has filed sex trafficking charges against him, saying that with the help of mostly female assistants, he blackmailed and coerced women into unwanted sex. Prosecutors hinted in earlier papers that Mack was one of the co-conspirators; it’s not clear who else may be charged.

Raniere’s attorney has said the facts would show Raniere did not compel or pressure anyone to do anything. He says everyone was acting in accordance with his or her free will at every instant.

Raniere sold himself as a self-improvement guru to the stars and his core disciples who include actresses, wealthy heiresses and a son of the former president of Mexico.

Founded in 1998, NXIVM promoted Raniere’s teachings as a kind of mystical, executive coaching designed to help people get the most out of life. Enrollees in its Executive Success Programs paid handsomely for his advice. The organization also drew criticism from people who likened it to a cult.

Last year, the accusations took a new twist, with women who were part of a NXIVM subgroup coming forward to say that they had been physically branded with a surgical tool against their will.

Prosecutors said in court papers that Raniere created a society within NXIVM called “DOS” — an acronym based on a Latin phrase that loosely translates to “Lord/Master of obedient female companions.” Women were required to provide damaging material about their friends and family, naked photos and even sign over their assets as a condition for joining, they said. Many were branded with his initials, they said.