In his new cover story with The Hollywood Reporter ... 50 claims Roc Nation attempted to keep him off the Emmy Award-winning spectacle alongside Dr. Dre, Eminem, Snoop Dogg, Mary J. Blige and Kendrick Lamar.

In fact, 50 says Em turned renegade and threatened to remove himself if 50 got banned ... "Eminem wouldn’t do it without me," he recalled to the outlet.

Fiddy continues ... "That’s how I ended up on the show because he was not coming if I didn’t do it. When that happens, you go, 'Damn, so you just lost Eminem because you didn’t bring 50? Damn. All right. Bring 50 then.' But if it was up to them, they would not have me there. I’m the surprise. I’m not on the bill at all. But they couldn’t get Em to do it without me."

While 50 did not explicitly say Jay's name -- the implication is clear ... especially since Roc Nation is Jay-Z's company, and everyone knows he's a honcho on SB programming now.

50 and Jay have been entangled in a rivalry since the G-Unit rapper's inception stemming from his infamous 1999 record "How To Rob" which put Jay and several other hip hop stars in 50's lyrical robbery on the track.

He and Jay collaborated on 50's "I Get Money (Remix)" single, which ironically also featured Diddy -- but that was strictly business, 50 says. In any case ... it would seem there's a bit of lingering bad blood between himself and Jay -- assuming what he's claiming here is true.

BTW, the other superstar in the Carter household -- Miss Beyoncé Knowles -- didn't get spared in THR interview either ... 'cause 50 made allegations against her as well.

When asked about his thoughts on the Grammys, 50 says the shiny trophies not only have "ZERO VALUE" but floated an unsubstantiated theory that Beyoncé's many wins over the years are an inside job. He explained ... "I don’t know who’s voting in that s***. It’s crazy. Whoever they are, they’re off at Beyoncé’s house because she has 30 of them."