The Masked Singer” is television’s top secret. The reality competition show goes to great lengths to keep the identities of the celebrity characters under wraps for the audience. In fact, the crew, director, cameramen, judges and even host Nick Cannon are left totally clueless about who is under the mask, just like the viewers.

Turns out, even Seal’s own children were left in the dark, and had no idea their father was competing as the Leopard for the entire season.

“Leopard wanted to do the show because he wanted to surprise his kids. They still didn’t know that he was on when the episode reveal aired,” showrunner and executive producer Izzie Pick Ibarra tells Variety. (Notice, she refers to Seal as his character name, not his actual name, which is standard secret-keeping practice on “The Masked Singer” set.)

“He did the whole thing to surprise his kids and make them laugh,” the showrunner shares. “I really wanted to send a camera, the moment that his kids see that it’s him, but we couldn’t, unfortunately, for various reasons.”

Asked how it’s logistically possible that Seal’s own children wouldn’t notice that their dad was participating in the singing competition show for the entire season, Ibarra explained the process of concealing the singer’s identities, which begins with producers asking the celebrities for a list of every person they want to tell about their involvement before filming begins. Those few people are then given NDAs and sworn to secrecy.

“No one else is allowed, unless they’ve been pre-approved with an NDA, so it’s not like they can bring people in-and-out of the production,” Ibarra explains.

“We encourage them to not tell as many people as they can. We tell them not to tell their kids a lot because it’s hard for kids to keep secrets, and it’s not really fair of them, obviously — when you are 7 or 8 years old, you don’t necessarily understand not telling people something,” the showrunner says.

“I know that the Unicorn, Tori Spelling, had a tough time with that in Season 1,” Ibarra shares, explaining that Spelling’s children’s peers were constantly asking if their mom was on the show.

In order to keep everything under wraps, Ibarra says contestants are never referred to by their real names on set, or even in paperwork. The initial talent contract will have the celebrity’s real name, but does not include the show name, “The Masked Singer,” just in case something leaks. And every other piece of paperwork only refers to the talent by their character name.

“We don’t call them by their names, ever. We only call them by their costume name,” Ibarra confirms.

Only roughly 25 people across the network, production companies and in production know who the celebrities are — and that’s including including legal, which has to oversee paperwork. Certain people in choreography know the contestant’s identities because they have to work with them in training, and the vocal coaches know the singers that they’re working with.

“None of the production team would know. Most of our field team does not know because they do not need to know. If you sit in our control, room, most people do not know. It’s hilarious because you come into the control room, everyone starts guessing in rehearsal. It goes on all day,” Ibarra says. “Unless it makes it impossible for you to do your job, there is no reason to know.”

The show also works with the talent to help conceal their identities, even more than keeping a giant mask on their heads and altering their voices. When celebrities sign onto the show, they go through special training, in addition to vocal training and choreography. “We try to hide their natural body language and mannerisms that they make, so we give them different mannerisms that they work with,” Ibarra explains.

Ibarra says that Seal’s reveal was especially fun for host Cannon, who knows Seal from his time working with his ex-wife Heidi Klum on “America’s Got Talent,” which he used to host on NBC, before hosting “The Masked Singer.”

Seal, a.k.a., the Leopard, was unmasked on Wednesday night’s semi-finals, along with The Thingamajig, who was revealed to be NBA player Victor Oladipo.