She told Ryan Seacrest's 102.7 KIIS FM show: "Yes, it's something that I would have loved to do, actually. But our schedule doesn't allow and it's a demanding schedule to be on that show.
“You have to be around months at a time, which is impossible for me."
So far L.A. Reid and Cheryl Cole have been confirmed for the gig, and that last judges spot is up for grabs.
Nicole Scherzinger, Jessica Simpson and Katy Perry all want the gig, but Simon admits he's having a really hard time narrowing down the options.
"You make a decision, then you get nervous about it, then you wake up in the middle of the night saying, 'I've made a terrible mistake.' You call everybody the following day to say you've changed your mind and then 24 hours later you go through the same process again.”
Jessica would be a great addition to the show. Sure, she's barely a singer anymore, but she made a name for herself with a mediocre voice, so I'm sure she can help other struggling artists.
Who do you think should fill the last seat?