You might remember Ja Rule's 2004 hit "New York" which featured Joe and contained a line where the rapper makes reference to Roy's career struggles at the time, having been KO'd by Antonio Tarver.

"Even Roy Jones was forced to lean back," went the line.

Roy was none too pleased about the line -- which he interpreted as a diss -- and according to Joe actually threatened to beat the hell outta him, although in the end cooler heads prevailed.

Joe says they're all on good terms now.

We reached out to Roy about the whole thing ... and he confirmed to us it's 100% true, saying he was "furious" at the time ... but he's let it go.

So, all is well ... now listen to the track. It's still fire!