"Mariah Carey is a true global icon -- one of the most accomplished artists on the planet -- and we feel extremely fortunate that she was able to bring her wisdom and experience to the 'American Idol' contestants this season, " they said.

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In American Idol's case, a team of roughly 15 people tailors the second screen experience for each week's contest developments.

ENGADGET: The state of the second screen: Will TV companion apps proliferate or dwindle?