Looks like Nelly wants both of them:
St. Louis rapper Nelly is stated to be planning a collaboration with Janet Jackson and Mariah Carey. Jermain Dupri is revealed as saying that the rapper is refusing to take no for an answer on having them join him in the studio.
The "So So Def" CEO and founder Jermain Dupri told MTV in a recent conversation, "Nelly's got a crazy collaboration he's trying to put together, which is him, Janet and Mariah Carey all on one song. That's what he wants. If he could convince them to do it, it would be crazy. He wants Janet to rap a 16-bar verse, he wants Mariah to sing the hook and he's gonna do two verses. He has it all planned out. You ask him about it! This is what he wants; he's 100 per cent deadlocked into it."
One question though: who are all of these people?