With the entire music world down at SXSW, Nas took the opportunity during his Mass Appeal showcase last night to preview some new music that he has with J Dilla that is produced by Madlib. The song, “The Sickness,” will presumably appear on the upcoming Dilla album, The Diary, which will feature a number of his vocals that were lost over time. Along with Madlib, the project will feature contributions from Snoop Dogg, Pete Rock, Bilal, and more. Of course, the album will also include some unheard production from Dilla in addition to his lost vocals. Though just a preview, “The Sickness” is what anyone would want to hear out of a Nas and Dilla collaboration and is a real reminder that Dilla was taken from the world way too soon. You can check out the full tracklist for The Diary and pre-order the project on iTunes before it drops on April 15 right here.