"Royce and I started hanging out again and inevitably that led us back into the studio," said Eminem. "At first we were just seeing where it went without any real goal in mind, but the songs started to come together crazy, so here we are."

Added Royce, "I'm excited to see this project come to fruition considering the long lapse in time between when we worked before and now. We had a blast doing it and we just hope everyone enjoys it while we're working on the 'Monster' that will be the Slaughterhouse album. #TeamShady."

The two first met in 1997 at a concert in Detroit and soon formed Bad Meets Evil (Royce as Bad and Eminem as Evil). But they released just a few recordings, including the song "Bad Meets Evil" on Eminem's major label debut, The Slim Shady LP and a heralded independent Bad Meets Evil 12" featuring the now underground classic, "Scary Movies." The pair went their separate ways in their solo careers only to be separated by a reluctant feud, thus making it the last time they would be heard together for several years.

Sadness over the tragic shooting death of mutual friend Proof in 2006 led to mended fences with Eminem's group D12, which prompted an eventual reconciliation between the two rappers. Eminem and Royce were finally once again on speaking terms after Royce was featured on D12's 2008 mixtape Return Of The Dozen and later went on tour with the group.

Since then, Royce has continued his acclaimed solo career (three of his four officially released albums, most recently 2009's Street Hop, have cracked the Top 40 R&B/Hip-hop chart). With rap stalwarts Joe Budden, Crooked I and Joell Ortiz, he has also formed Slaughterhouse, recently signed to Eminem's Shady Records. In addition, Slaughterhouse contributed a bonus track to the digital deluxe edition of Eminem's blockbuster 2010 Recovery album.