GNR, Def Leppard, Deep Purple, Collective Soul Supergroup Plan EP
The EP revelation came during the band's "pre-concert hype" for the concert, according to a Rolling Stone South Africa's Doug Davenport who spoke with the band's ringleader Duff McKagan (Guns N' Roses, Velvet Revolver).
The supergroup revealed that they are currently working on writing original material for the EP as they travel across the globe performing their collective hits. However, they apparently did not offer a time table for when they expect the EP to be released.
You can read the Rolling Stone report for a full review of the show, which gives you an idea of the star power involved in this group, and also stream their exclusive interview with McKagan, here.