It was not a well kept secret, but it is now all official.  Keith Urban is officially a judge on American Idol.  He will join Randy Jackson, Mariah Carey, and Nicki Minaj on the panel. 

Sunday, Keith tweeted the news.  "SO excited to be joining the team on @AmericanIdol!!!!!! -KU #idoljudges."

Since last month, it was widely rumored that Urban would land a job as an American Idol judge.  He also recently left his job as a judge on the Australian version of The Voice.