So much for that truce. Nicki Minaj and Mariah Carey's rumor feud on American Idol is hitting new heights, with Minaj allegedly threatening to 'knock out' her fellow Idol judge at Tuesday's auditions in Charlotte, North Carolina.  The cat fight went on with Keith Urban sitting in between the two.

According to TMZ, the two had a big fight on the set. At one point Nicki left, but came back and the fight continued. That's when Nicki began swearing and threatening Mariah. Things got so bad  producers ended auditions for the day so everyone could 'cool down.' Now producers are said to be worried about Mariah and Nicki 'co-existing for the long haul.'  I'm worried Keith is going to get caught in the crossfire.

Watch the cat fight video caught by TMZ.  Its a little hard to hear what Minaj is actually saying to Mariah but with all the bleeps, you'll get the gist.  Poor Keith just throws up his hands.