Show producers have been scrambling to fill the seats left vacant following the departure of Mariah Carey, Nicki Minaj and veteran producer Randy Jackson earlier this year (13), and have recently been in talks with producer Dr. Luke and Justin Bieber's manager Scooter Braun to help find the next singing star.
However, those negotiations fell through and executives at Fox, the network which airs the programme in the U.S., are said to have asked Connick, Jr. to return following a number of successful guest appearances on the series throughout the years.
According to The Hollywood Reporter, the jazz star made the deal official by attending a private party hosted by Idol producer Simon Fuller in Los Angeles on Thursday (29Aug13), where Urban and Lopez were also on hand to toast the imminent announcement.
Urban is the only star returning as a judge from the 12th season of Idol - Lopez stepped down from the panel of experts last year (12) after two seasons.
Connick, Jr. has been a longtime fan of American Idol and previously admitted he had been approached to take on a role as a talent judge years before - but the timing has never been right.
He said, "The last time I was here, I was so flattered, that they (producers) were kind of talking about it, and it didn't work out. There were a lot of things going on on their side and a lot of things going on on my side with just stuff. It's hard to make a commitment like that... What I've done thus far on the show has been really fun, so I've had a great time... Who knows what'll happen in the future."