When Fat Joe began serving a fourth month bid for tax evasion in August 2013, it had been about a year to the day that revered hip hop executive Chris Lighty passed away. Joe would later be released early, after three months, just in time for Thanksgiving, and one of his first moves was to contact DJ Kay Slay.

Slay, a mixtape master known for refereeing MC battles, had Lighty in mind when Joe called. Joe gave Slay a track and told him he could put whoever he wanted on it. Slay's first thought: 50 Cent.

"The only thing Chris wanted to do was dead the beef between Fat Joe and 50 [Cent]," Slay told BET.com. So, Slay put 50 on the track, making his recently released "Free Again" the first time ever the formerly feuding New York rap giants appear on a song together.

"I figured if that's ever gonna happen, this was the chance now," Slay said. "So, you know, I hit 50, he told me, 'Come to my office.' I let him hear the track, and I came by and played the beat, and he was like, 'Yo, I'm on this.'"

He promises, "I ain't blindside nobody." Well, maybe the listeners. 

Slay dropped the track on Funkmaster Flex's show last week, complete with Raekwon's vocals and as a prelude to his next album, Rhyme or Die. The project is designed to help restore the respect for New York rap in general and lyricism in particular.

"The beef thing is somewhere else right now. It's not what it used to be, it's not about lyricism," Slay said, explaining that hip hop battles have become more about Instagram flexing and Twitter beefs than actual spitting. Rhyme or Die (which "Free Again" may or may not appear on) he says, will end all that.

"It’s 16 tracks, straight hip hop, all your favorite artists on there — lyrical artists — everyone from Raekwon, Ghostface, Jim Jones, you know, Kendrick Lamar, Mac Miller, Bun B, Rick Ross on there, you know, just lyrical artists all over my project," he said. "I been in the game since hip hop was birthed, so I know the difference between a rapper and a true MC."

What's a true MC? "When I send somebody a beat and they just do what they need to do on it."

Rhyme or Die, Slay's fourth studio album, is slated for release this spring ("May," he said, "just before summer.").

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(Photos from left: Moses Robinson/Getty Images for BET, Andy Kropa/Getty Images)