Slim Shady raps about almost signing to Duck Down, and Buckshot explains why he and his business partner are OK that he didn't.

Before Eminem became one of music's highest-selling artists, Slim Shady was a fixture in hip-hop's underground, and no matter how many records he's sold, he always manages to pay homage to rap's underground kings.

On "Don't Front," a Marshall Mathers LP 2 bonus track that's available to fans who purchase the"Call of Duty: Ghosts" video game, Em borrows from Black Moon's 1993 track"I Got Cha Opin" and even reached out to group's frontman, Buckshot,to add vocals to the revamped version.

It all began with a phone call to Drew "Dru Ha" Friedman, Buckshot's business partner in Duck Down Music, a longstanding independent hip-hop record label. "He called Dru and Dru called me on a Thursday and told me about it and said, Em did'I Got Cha Opin,' the original, off the album," Buck told MTV News on Tuesday.

After he got the phone call, Buck flew to Detroit the next day to work with Em and lay down the hook for the track.

Hip-hop history buffs will recall that there were two versions of Black Moon's "I Got Cha Opin." There was a bass-heavyalbum version and then there was the more melodic remix versionthat was serviced as a single to radio. Em chose the grittier of the two to re-create. "They're definitely two different vibes and that's a raw track, the original. So I was real happy that he took that," Buck admitted, though we can't imagine he'd be upset if Em decided on the remix instead.

The veteran Brooklyn MC crafted hip-hop favorites like "Who Got the Props?" and "How Many MC's..." with his group Black Moon, and as one of the heads of Duck Down helped introduce acts like Smif-N-Wessun, O.G.C. Heltah Skeltah and Sean Price into the game. There were talks of bringing Eminem onto the Duck Down roster, but that was before Dr. Dre took notice of the rising star and signed him to put his The Slim Shady LP album out on Aftermath/Interscope in 1999. Marshall raps about it all on the new track.

"Almost forget, before I signed with the Doc/ I almost signed with Duck Down/ 'Cause Rawkus didn't make no offers and mother---- loud, they jerked me around/ So wassup now," he spits on "Don't Front," showing love to Dru and Buck and spewing a bit of venom at Loud and Rawkus Records, two powerful back-in-the-day rap labels that passed on signing Em.

"Yeah, we do have a history with Em and Eminem stated that in the second verse," Buck said before acknowledging that even though Marshall didn't ink with his company,things worked out for the best. "Dru Ha was supposed to sign Em, but I'm glad he didn't sign with Duck Down, I'm so glad he didn't 'cause everything happens for a reason."