Cuba Gooding Jr. -- He's the Perfect O.J. Simpson ... Says Kato Kaelin

Cuba Gooding Jr. is the PERFECT guy to play O.J. Simpson in an upcoming TV miniseries ... so says someone who would know -- Kato Kaelin.

We spoke with O.J.'s most famous house guest about reports that CBJ will portray "The Juice" in an upcoming FX miniseries called, "American Crime Story: The People v. O.J. Simpson."

"Cuba's my friend. I think he's gonna do great," Kaelin told us.

Kaelin says Simpson "had an arrogance to him" ... which Cuba will have no trouble nailing down.

"I think [O.J.'s personality] is a lot like Cuba's character in 'Jerry Maguire.' He wanted the attention ... that was pretty much O.J. Simpson."

For the record, Rod Tidwell never killed anyone ... allegedly.