Kim Kardashian may be one of the most popular celebrities in this world, but not everyone keeps up with her lavish lifestyle, including Mariah Carey.

Nick Cannon spoke with Howard Stern on Tuesday about his infamous sex list, which includes Kardashian, Nicole Scherzinger, supermodel Selita Ebanks and Christina Milian. But, when the radio personality asked if Carey was concerned about his past life with Kardashian, Cannon revealed that he wife doesn't even know of Kardashian.

"The one that [must have gotten] Mariah the most pissed was [when] you talked about Kim Kardashian, that you f--ked her, and that really got Mariah's goat," Stern said to the actor.

"You know? I don't think ... no, 'cause, honestly ... my wife, she [doesn't] even know who Kim Kardashian is," Cannon responded.

"Right, she's on a whole other planet," Stern said.

"Yeah, she doesn't pay attention to that," Cannon added.

Cannon also said that Carey isn't concerned with his past sex life because they currently have a strong marriage.

"She doesn't care when I talk about our sex life, because our sex life is amazing. She's one of the most beautiful women in the world."

The father of two also admitted that Carey has a tendency to fire nannies every other week.

"Everything's on a trial basis," Cannon added. "It's just like, hey, we're gonna see how this works out. And we're always traveling, so the nanny might not get a plane ticket to the next city," he laughed.