Jay-Z Not Responsible for 1999 Stabbing of Lance 'Un' Rivera, So Says Rivera

Former music exec Lance 'Un' Rivera is clearing the air about his stabbing 24 years ago, saying Jay-Z absolutely did not do it ... and he insists prosecutors got it wrong when they nailed the rapper for the crime.

Rivera, best known for his affiliation with Notorious B.I.G., sat down with "Vlad TV" ... and got candid about the highly-publicized stabbing, for which Jay ended up getting 3 years probation just as his career was blowing up.

Rivera says Jay was in the nightclub on that fateful night, but he's not the one who stabbed him in the back with a large blade -- and adds, everyone knows Jay wouldn't have done something like that. However, he's not saying who actually did it.

This all goes back to December 2, 1999, when Rivera was stabbed leaving a release party for Q-Tip's Album "Amplified." He says Jay and other members of Roc-A-Fella Records approached him and accused him of leaking Hov's "Vol. 3... Life and Times of S. Carter" album.

Witnesses reportedly identified Jay as the stabber, and although he turned himself in to NYPD for questioning, he maintained his innocence.

He was arrested for felony assault charges, and after a 2-year-long legal battle, finally pled guilty in 2001.

Although he avoided prison time, Jay couldn't leave NY state during his 3 years of probation -- a major career hurdle, as it happened after the success of his Grammy-winning '98 album "Vol. 2... Hard Knock Life."

There's always been debate about what actually went down ... with Nas notably stating on his track, "Ether," that Jay-Z took the fall for a friend.