Connick, 45, will join Jennifer Lopez and Keith Urban for the upcoming season. The announcement comes a few days after it was reported Connick was in talks to join the panel.
The singer-composer has appeared on the show in the past as a performer, mentor and guest judge.
Former host Randy Jackson will also make a comeback as a mentor this season.
Sony Music is a rival of Universal Music Group, which holds the rights to all "Idol" recordings.
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