NXIVM: 'Smallville' Stars Tom Welling, Michael Rosenbaum Break Silence on Co-Star Allison Mack's Role in Cult

Smallville star Tom Welling broke his silence on former co-star Allison Mack's involvement in the scandalized NXIVM cult, briefly remarking on Friday that Mack had always treated him with kindness and that he didn't know anything about her complicity in the secretive — and now criminal — group.

"I was very surprised to read anything about it," said Welling, who starred alongside Mack throughout Smallville's decade-long run on the now-defunct WB Network. "It sounds very bizarre. Allison was always a nice person around me."

His comments came during an interview on the podcast "Inside of Me," hosted by Michael Rosenbaum, who also co-starred in the WB show, which spun around Superman's teen years and early adulthood.

Welling later added, "It's also funny that people think that we would know, or that we would have some perspective on it."

NXIVM claimed to be a self-help organization geared toward women's empowerment. But federal prosecutors claim the group, based outside of Albany, New York, was instead a cult lead by the charismatic Keith Raniere, who was found guilty of sex trafficking and conspiracy to commit forced labor, among other criminal charges, on Wednesday by a federal jury in Brooklyn, N.Y.

Mack was reportedly Raniere's second-in-command, recruiting women and leading a ceremony in which these recruits were branded with the pair's initials. She was also accused of blackmailing women who attempted to leave NXIVM.

The Hollywood actress pleaded guilty to racketeering charges in April as part of a deal with prosecutors.

In court, she apologized and said her involvement had been "misguided."

"I must take full responsibility for my conduct," she said. "I am very sorry for my role in this case. I am very sorry to my family and to the good people I hurt through my misguided adherence to Keith Raniere's teachings."

During his podcast, Rosenbaum said he was aware that Mack was involved in a self-help group but had no reason to suspect it was anything nefarious.

"I remember one time, maybe it was Allison who asked me...she was just like, 'Hey, you should try coming to it,'" he recalled, "and I was like, 'No. I don't know. It's not for me.'"

He continued: "I don't know what to say, other than if it's true, it's a tragedy."

In a previous interview with Newsweek, Former NXIVM publicist Frank Parlato described Mack as both a victim and perpetrator of abuse.

"Poor Allison unfortunately got caught up in the cult," Parlato said. "She sincerely believed that it was going to teach her things that would make her a better, more spiritual, more critical-thinking and logical type of person."

Allison Mack
According to a criminal complaint, Keith Raniere ran a sex cult. “Smallville” actress Allison Mack was his No. 1 co-conspirator, according to a criminal complaint. The actress pleaded guilty to racketeering charges in April. Keith Raniere Conversations/YouTube