Rap mogul Jermaine Dupri has ended weeks of speculation by confirming he is definitely working on a duet between Janet Jackson and Mariah Carey. Carey insisted she knew nothing about the reported collaboration during a recent interview, but confessed she was a big fan of Jackson's. But now Dupri, who is dating Jackson, admits he's working on the track that will bring the R+B heavyweights together on record for the first time. He tells MTV News, "I got a mean idea, so look for it. It's gonna happen... Please believe that." And producer Dupri, who is largely responsible for Carey's 2005 comeback, insists the duet could be wrapped up in time for the repackaged release of Jackson's much-anticipated new album 20 YEARS OLD. He adds, "We're definitely gonna do a repackage on the album once it comes out. Hopefully it's successful and people buy into it, then I'm going back in the studio. "The closer I get to that idea (for Janet and Mariah), the more I know where it should be at. It's feeling like it's gonna happen."