Mariah, Justin, French, T.I. Join Forces in Song 'Why You Mad?'

EXCLUSIVE

Mariah Carey has been secretly recording a new song that we think will blow you away.

She went to a recording studio in Hollywood last week and laid down tracks with French Montana and T.I.  As we reported, Justin Bieber showed up on one of the recording nights and joined in, and he's amazing.

The song -- "Why You Mad?" -- has not been released, but we got hold of a copy.

Enough said ... judge for yourself, but if you don't love it you're kind of crazy.