Arch conspiracy theorist Alex Jones has “scooped” Megyn Kelly and released a secret recording from their controversial interview in which the NBC star promises him she is not preparing a “gotcha hit piece”.

Ms Kelly, one of the country’s most high-profile anchors, had sparked outcry by interviewing Mr Jones for a show that is due to be broadcast this weekend. The families of some of the children killed at the Sandy Hook massacre have threatened to sue NBC, over comments Mr Jones makes in a teaser of the interview in which he repeats his claim that the 2012 incident in which 26 people lost their lives was a hoax.

Now, ahead of the NBC broadcast, Mr Jones has posted on social media a secretly recorded conversation between himself and Ms Kelly.

“All I can do is give you my word. If there is one thing about me, I do what I say I’m going to do, and I don't double-cross,” Ms Kelly tells Mr Jones in the recording.

“You know you just became very fascinating to me. I just always thought you were this maybe, one-dimensional guy, like this is your thing.”

She adds: “My goal is for your listeners and the left - you know, who will be watching some on NBC - to say, ‘Wow, that was really interesting’.

Megyn Kelly sparks outcry for giving Alex Jones’ platform to repeat Sandy Hook conspiracy theories

“And then the next time I wanna get somebody, they’re gonna say, ‘Look what you did to Alex Jones’. It’s not going to be some gotcha hit piece, I promise you that.”

Mr Jones has promised to release his entire recording ahead of the NBC broadcast.

“Infowars is preparing to release tonight the full Megyn Kelly interview with Alex Jones originally set to air on NBC this Sunday evening,” says a post on his website.

“Kelly’s first promo for the show, published on Twitter last Sunday, contradicts the host’s private statements to Alex Jones in which she claimed the interview would not be a blatant hit-piece.”

NBC has found itself trying to fight off the controversy over the decision to provide a platform for Mr Jones, who also claims that the 9/11 attacks were an “inside job” perpetrated by the US government. 

A number of family members of those who were killed or injured at the Newtown elementary school by shooter Adam Lanza, have written to the network criticising the decision to broadcast the interview. 

The Los Angeles Times said some of them had now threatened to sue the network if the broadcast goes ahead.

Ms Kelly has defended the decision to interview Mr Jones, saying on Twitter that it is her job to “shine a light”.

NBC News Chairman Andy Lack told the Associated Press that the story with will be edited with the sensitivity of its critics in mind.