Fergie, Adam Lambert, and Mariah Carey Credit: Michael N. Todaro/FilmMagic; Joseph Okpako/WireImage.com; FADEL SENNA/AFP/GettyImages

Reportedly departing American Idol after two seasons as a judge, Jennifer Lopez is leaving the FOX series with big shoes to fill on the judges' panel alongside Randy Jackson and Steven Tyler.

Among those reportedly being considered for Lopez's Idol spot: Mariah Carey, Fergie and Idol's season 8 runner-up Adam Lambert. Though E! News reported that FOX execs have been in talks with Lambert, 30, "for over a month," a production source counters to Us Weekly that no final decision on Lopez's replacement has been made.

"It's true they've talked to Adam but nothing is decided yet. Fergie is another big contender," says the source. "Adam would be an awesome addition to the show -- he could really relate to the contestants and he's such a good guy. It will be a little while before there's any decision. They are considering a lot of people for the panel."

Mom of twins Carey, 42, has long expressed interest in taking a seat on the panel, and was said to have been considered back in 2010 before Lopez, 42, agreed to appear on season 10. "[Mariah] wants it," E! News reported at the time. "She's seen what America's Got Talent has done for [husband Nick Cannon] and she thinks it will be a good career move."

Though no bold-faced names have signed on the Idol dotted line just yet, one thing is for certain: Lopez will not return to the series, as hard as FOX may court her.

"There is just too much going on for her right now," says an insider of Lopez, whose tour dates conflict with Idol's shooting schedule. "She regrets she can't stay on the show. It's been an incredible experience and she is forever grateful that she did it."

No official announcement about Lopez's season 12 Idol contract has been made.