The person said Monday that a deal is close to being signed with Lopez, who was an "Idol" judge for the 2011 and 2012 seasons. The person wasn't authorized to comment publicly and spoke on condition of anonymity.
The person says Lopez decided to rejoin the show because its production schedule will allow her to spend more time with her children, 5-year-old twins Emme and Max.
Lopez will join returning judge Keith Urban and a third person who hasn't been announced.
Fox has declined to comment on whether Lopez is joining "American Idol" and did not immediately respond to another request for comment Monday.
Lopez's agent did not immediately respond to an email seeking comment.