LeBron James Rap Session is EPIC -- I Got Yachts, Watches and RINGS!!!

LeBron James has finally recorded an entire RAP VERSE (and even laid down the hook) during a private studio session with a friend ... and TMZ Sports has the exclusive audio.

'Bron and his childhood friend Sian Cotton hit up a recording studio in Ohio last summer and busted out a remix of the Jay Z club banger "F**kwithmeyouknowIgotit."

During the song, which LeBron and Cotton titled, "Kingdom" -- James raps about docking his yacht off the coast of France, having "money, cribs and whips" ... and most importantly owning TWO NBA CHAMPIONSHIP RINGS!

We spoke to Cotton who tells us the two never really planned to record the song -- it was a spur of the moment decision made during a gym session.

"We were working out together and LeBron said 'let's get in the booth.' I said 'I'm going tonight', so he came to the studio."

Cotton -- an aspiring rapper who just released his new mixtape (featuring his new song "Ancient Mayans") -- adds, "We were just having fun. Bron had jotted some notes down earlier, and he finished his verse in the studio."

Bron has dabbled in rap before -- and once released a VERY brief sample of his skills ... but nothing like this.

Here are the lyrics to LeBron's verse:

[LBJ Hook:]
Ugh, roll, roll with us, cause you we got it, (we got it, we got it)
roll with us, cause you know we got it, (we got it, we got it)
it's a damn shame that you ever doubted, (doubted, doubted)
come roll with us cause you know we got it (we got it, we got it)
roll with us cause you know we got it (we got it, we got it)
roll with us cause you know we got it (we got it, we got it)
it's a damn shame that you ever doubted, (doubted, doubted)
it's a damn shame that you ever doubted, (doubted, doubted)

[LBJ Verse:]
I just docked us off of France killa
Shots so bright I got a tan killa
Try to catch up it's a waste of time (waste of time, waste of time)
I grind you hard let you take mine (never, never)
AP watch drop next month (month, month)
60 racks on ya wrist to stunt (stunt, stunt)
Fall back before you fall out
My team eating, the rest of y'all drought (drought, drought)
Say what you want about the king,
Got money, got cribs, got whips, and oh yeaaa (bleeped) got 2 rings (2 rings, 2 rings)
Cribs sick, tall like, Costco's,
Gotta keep getting that Robert, DeNiro, don't fear you
I understand you can't compete bro, but you see here, is royalty,
You can't beat me, ya better join me, over at six feet, underneath (underneath, underneath)

Where my crown Shi (where my crown Shi, where my crown Shi)