Check out this clip of Mariah Carey being interviewed by a German television reporter. If by chance there's some reason you don't know German, the reporter first asks Carey about Beyoncé to which Carey responds with gushing compliments. When the subject turns to J-Lo, Carey's expression suddenly changes and she says "I don't know her." Around the 45 second mark, the reporter peels off her face revealing that it's actually been J-Lo asking the questions the entire time. The two divas then engage in an epic fight rivaling the best Godzilla-Mothra battles. And then they both start making out before finally going down on the cameraman for what seemed like a good ten minutes. A little surprised this hasn't gotten more play in the press...
Mariah doesn't like her, so it's Mariah's version of trying to be graceful. She's accused JLo of not doing her own vocals before, if I remember correctly?