Actress Allison Mack told a Nxivm slave who was molested as a child that the best way to “heal” was to have sex with their creepy leader, the woman testified Tuesday.

“This is going to help you get rid of all your sexual-abuse trauma,” the TV “Smallville” star allegedly told then-member “Jay,” while urging her to sleep with accused sex-trafficker and cult leader Keith Raniere.

“And I give you permission to enjoy it,” Mack added according to Jay, who testified at Raniere’s Brooklyn federal-court trial Monday that she was repeatedly molested by an uncle at age 12.

Jay — the alleged former slave of Nvixm member India Oxenberg, the daughter of ex-TV “Dynasty” star Catherine Oxenberg — said this was the moment she realized, “I need to get the f- -k out of here.

“Internally, I was just like, ‘you f–king bitch,’” she said of Mack, one of Nxivm’s alleged slave masters.

“I was horrified and enraged with the fact that she would try to re-traumatize me, [saying] that doing something sexual with someone that I didn’t want would heal my sexual trauma.”

But Jay said the “emotionally abusive” Mack told her that it should be “an honor and a privilege” for her to sleep with Raniere.

The former slave said Mack told her, “Me and India have been talking. We wanted to give you this special assignment.

“The assignment was for me to seduce Keith and have him take naked pictures,” Jay said.

But India allegedly ordered her slave not to wax — because Ranierie liked his women with a lot of pubic hair.

Raniere considered waxing “propaganda from the porn industry perpetuating violence against women,’’ Jay said India told her.

Jay said she freaked out when she eventually Googled Raniere and the group and began planning her escape.

Her time with Nxivm was less than a year, from around the end of 2016 to mid-2017, Jay said.

Before she left, Jay said Mack asked her, “Are you saying you think I’m an accomplice to a child molester?’’

“Yes,” Jay said she replied.