Charles Barkley Gives Post-Prison Advice to O.J. Simpson

Charles Barkley is rooting for O.J. Simpson -- telling TMZ Sports he really hopes the guy can "keep his act together" after prison ... and he's offering up some advice to stay out of trouble.

Unclear if Barkley and Simpson were friends before he went to prison, but it seems Sir Chuck feels bad for the disgraced NFL running back, judging by the clip.

Charles also makes it clear he wasn't impressed with the way O.J. handled himself during his parole hearing last week -- saying, "He's done everything possible to screw this thing up."