Sports Business Journal recently took a look at CM Punk’s surprise debut on the WWE Backstage show earlier this month.

It’s no secret that FOX took great lengths to keep Punk’s debut a surprise, as revealed in a behind-the-scenes video here, but SBJ reports that only a half dozen people of the two dozen people in the production room knew Punk was appearing. It was noted that half of the control room gasped when Punk came out, and the other half cheered.

Punk is signed to a FOX contract, not a WWE contract, and network officials really wanted to make sure news of the appearance did not leak.

“Part of what we’re doing with this show is shock,” said Brad Zager, who is FOX Sports’ Executive Producer, Executive Vice President, Head of Production & Operations. “You heard that natural reaction from our control room not believing that this was really happening. We wanted to make this a surprise. We wanted to make this a moment.”

SBJ noted that the weekly WWE studio show is produced in the same studio as “FOX NFL Sunday,” but has a different look and feel than a traditional studio show, down to the need to deliver a show-closing tease to bring viewers back for next week. Zager commented on the first big challenge they faced with producing the show.

“The first challenge we had was figuring out how to produce this show without making it feel like we’re putting the WWE superstars and our host behind the NFL on Fox desk and calling it a day,” Zager said. “That started with the look and feel of the show ? building a wrestling ring on set and creating an environment where these guys can feel natural.”

It was confirmed that Punk didn’t sign his FOX contract until the week before his debut. All sides had promised to keep the news quiet. Punk, Zager and Jacob Ullman, who works as FOX Sports’ Senior Vice President of Production & Talent Development, were out at dinner the night before the show, and all three were surprised the news had not leaked.

“We had to buck the trend and not let it leak,” Zager said. “It was the tightest circle of people to ever know about something that we’ve done.”