Eminem recently justified the delay on Dr. Dre's long-awaited Detox album and said his studio work with the producer forced the project to be pushed back.
In addition to confirming the album does exist, Slim Shady also offered brief details surrounding the forthcoming release.
"With Dre, Dre's got a lot of material for this record," Em revealed in an interview. "And he's recorded a lot of material. I think that more so than anything, before his album, he basically put aside, he was working on his record for a good time period, I would say probably a year, a year and some change straight, he was working on his record and he basically put that on hold once we got on the road with my record, which I'm extremely grateful for you know."
Source - http://www.getrightmusic.com/videos/2009/05/23/dj-semtex-interview-with-eminem/