'Grand Theft Auto V' Star -- History Of Violence With Ice Cube ... But 'That Sh*t's Over Now'

Back before he voiced Franklin the gangbanger in "Grand Theft Auto V," Shawn Fonteno was a rapper who allegedly KNOCKED OUT Ice Cube in a legendary street fight ... TMZ has learned.

Fonteno used to rap under the name Solo -- and back in the day, he appeared in the documentary "Beef 2" describing a fight with Cube, in which he claims he KO'd the rapper over a business dispute and stole his chain.

The story was huge back in the '90s ... and the incident was a big part of the nasty feud between Cube and Cypress Hill, since Solo was tight with CH (scroll to 9:57 in the YouTube clip).

But now, Fonteno has grown up ... and this week in L.A., the voice actor told us he's buried the hatchet with his former foe.

"We both hustlers homie, it is what is, you know what I’m sayin’?" Fonteno told us.

"He’s from South Central, I’m from South Central, that sh*t’s over with man."