US Weekly reports that 'Who I Am' singer Jonas and rapper Pharrell are at the top of the list for Idol execs to fill the remaining slots following the departure of Steven Tyler and Jennifer Lopez.
"Nick is pretty close to signing to be the Idol judge. They flew him in to LA last week for final meetings," an insider told the publication.
As for Pharrell's official progress, the source added: "Everything is looking good, but they're still working out details."
Fox reps have declined to comment on the story.
Earlier this month, Mariah Carey officially signed a deal to join the judging panel and is rumoured to be earning an unprecedented $17 million for American Idol's 12th season.
Country star Brad Paisley was recently reported to be in the running for a spot on the panel.