The pair will join pop star Mariah Carey and Randy Jackson, the only remaining original Idol judge.

The announcement came just hours before initial auditions for the next season in New York.

“I am thrilled about this year’s judges’ panel!” said Mike Darnell, president of alternative entertainment at the Fox Broadcasting Company.

“Nicki’s an unbelievably captivating international phenomenon who has made an indelible mark on rap and pop. And Keith is another great addition to Idol — he’s one of the biggest stars in country music and I know that our fans and contestants will fall in love with him.”

He said the now-complete team was “one of the most exciting judging panels around.”

Pop diva Jennifer Lopez and Aerosmith’s Steven Tyler announced in July their departure from the show, which is struggling against rival The Voice on NBC.

American Idol has aired for 11 seasons, but was thrown into disarray by the departure of judges Simon Cowell, Ellen DeGeneres and Kara DioGuardi two years ago.

But Marc Graboff, president of the CORE Media Group that owns Idol producer 19 Entertainment, insisted that season 12 would be “terrific.”

“Idol has truly never looked better,” he added. “We couldn’t be more pleased about this new team of judges.”

A person in the music industry with knowledge of the deal said that the singer-rapper will receive $12 million for a one-year contract with the hit Fox singing series.

The person spoke on condition of anonymity because details of the contract had not been made public.