"I was surprised because Simon has always been against the fourth," she said. "We've had guest judges come in before and he banned that from happening anymore. I didn't understand the concept of what was happening."
Fellow judge Randy Jackson said that the four judges have a family dynamic, with "friendly camaraderie."
"Simon, Ryan, and I are best buddies, I guess we have a bit of a bro-ish-mance or something," he joked. "It's kind of like big brothers and sisters. That's what it is, it's really like brothers and sisters."
Abdul said she already knew DioGuardi. Ironically, she helped the aspiring songwriter break into the industry.
"Well, I started her success. And I'm proud of it ... happy of it," Abdul said. "I moved a stranger from New York, told her to give two weeks notice to Billboard magazine and moved a stranger into my home in L.A."
And while that may sound odd, Abdul has also played an influential role in the careers of many others. As an Emmy-winning choreographer, she worked with stars like Eddie Murphy and Michael and Janet Jackson. She even choreographed the famous keyboard scene in Tom Hanks' classic, "Big."
When asked if she thought DioGuardi would replace her, Abdul said, "I don't think anyone [can]. First of all, Kara says, 'I could never replace you.' And I said, whenever there is change, it's not about replacing anybody. It's about possibly moving on."
Fellow judge Randy Jackson said he doesn't think there's tension between Abdul and DioGuardi.
"There's tension among all of us because we're all a very dysfunctional bunch," he said. "I often say that to be in the entertainment business you've got to be at least a little crazy."
Further indications of a strained relationship between Abdul and "Idol" producers surfaced last November when an obsessive Abdul fan -- she called the fan a stalker -- committed suicide outside her home. The woman had been mocked at an "Idol" audition by Cowell.
"It's an ongoing investigation," Abdul said. "I'm not at liberty to speak about this right now because it's still an ongoing police investigation. It's tragic. ... There will be a day when I can talk about it. I just can't do it now."
Jackson said that while Abdul has had her ups and downs, he never worries about her.
"She's a trooper, she's one of the best artists, one of the best people I know," he said. "She's stellar right now ... I think this is one of her best seasons."
"This is totally reminiscent of when I started in the biz 20 years ago," Abdul said. "I feel like it is a magical time. No one can get in my way, not even me, believe me. I just feel like it's magical. I'm making a new record. .... What really matters is don't ever count me out."