Mariah Carey 'Nightmare' Bad Attitude Could Cost More Than $18 Million Contract (VIDEO)

Mariah Carey has just been signed on to join as the next "American Idol" judge but according to some, that decision may have been poorly made.

It was announced on Tuesday that Mariah Carey wouldn't be signing on to join the "American Idol" team at the contract price of $18 million dollars. While that price tag seems low to some, others have suggested that it is a hefty one considering the pop star's attitude.

"Mariah Carey was a 'nightmare to work with' during her brief stint as a guest mentor on 'American Idol' in 2008," a source close to the show reported to TMZ. "She was incredibly late for her shoot at the Beverly Hills Hotel, 'not very nice at all,' and ridiculously nitpicky about tiny details."

Such rumors, if proved true, could be troubling to the show and judge panel especially after Jennifer Lopez stated that balance was an important thing to have.

"It's such a delicate thing to find chemistry for that panel," she told Access Hollywood in an interview after she announced stepping aside from the show. "They're gonna have their work cut out for them. I think just to find that balance again and that magic that happens when the people sit there."

J.Lo on the other hand, was described as a "pleasure" to work with.

"In contrast, the same sources agree J.Lo was a pleasure – 'night and day' compared to Mariah. We're told J.Lo was all about business, in and out, no mess, no fuss," the insider told TMZ.

With Mariah Carey filling the second slot, only one spot is left and it appears that producers are still uncertain about who will make the panel complete.

"Dozens" of candidates are being interviewed, according to Wall Street Journal, who explained some of the necessary qualities of the next judge.

"You want a mix of star power and credibility," the source stated.

Some fans of the show, however, disagreed and suggested that the final judge should be more average than not.

"I think being 'American' Idol, an average American should be chosen to judge along with the 2 celebrities," James Dionysius stated on The Christian Post blog.