"[Mario and I] really hate each other," Kardashian, 28, joked to Ryan Seacrest when she called into his KIIS-FM radio show Friday morning. "I'm so sick to my stomach that I have to be by his side. You know, when [someone is] that unattractive, it's just hard to be with [them]."
But seriously, folks. "[Mario] is the nicest guy ever," she clarified. "He's great at what he does, so it takes some of the pressure off of me...I think we're going to have fun. We've known each other for a while, so I feel comfortable around him. He'll make it easy for me."
Kardashian and Lopez, 39, weren't publicly named as hosts until October 16, but Us Weekly reported the announcement on October 2, and even X Factor creator Simon Cowell called it the "worst-kept secret in Hollywood." It seems the only person who didn't know was Kardashian herself.
"Everyone thought I was just BS-ing [them]," she told Seacrest, who emailed his congratulations to the star before she had even heard the news. "They were like, 'So you got the job?' And I was like, 'I promise you, no one has confirmed anything with me. I would tell everyone if I did.' I was just waiting for someone to tell me. But everyone knew before me!"
Now that it's official, she said, she's thrilled about her new gig. But she does have a few pre-show jitters.
"I'm so nervous -- I've never hosted before!" the star admitted, adding that her fears are amplified by the live aspect of the telecast. "What if I get kicked off the show because I say something so bad? That's what I'm nervous about, but I can't be anybody else but myself. I just have to control the language a little bit."
Kardashian also copped to being a little anxious about interacting with judge Cowell, 53, whom Seacrest knows from their eight years together on American Idol.
"He enjoys it when you get very close to his face," the radio host joked of his former colleague. "And he'll get very distracted if you dress in something sexy, so I suggest you do...How do you think he and I got along for so many years?"
As for the rest of the X Factor crew -- which includes Cowell's fellow judges Britney Spears, Demi Lovato, and L.A. Reid -- Kardashian said she's "in good company." Of Spears, in particular, she added: "I've met her a few times. I wouldn't say we're best friends, but she's so sweet. She's been nothing but nice to me. And I know her fiance [Jason Trawick]. He's so nice. They're just really sweet people."