Will Smith Makes Surprise Visit to LAPD

Will Smith turned more than a few heads when he made a couple unscheduled stops at LAPD stations last week, but we've learned he meant business when he arrived.

Sources close to the actor tell TMZ, Will showed up last week at 2 stations -- including the Wilshire division -- to do a little homework for his cop role in the upcoming thriller "Bright." While he was there, we're told he personally thanked the boys in blue for their hard work.

Law enforcement sources tell us the visits -- he also hit up LAPD's downtown HQ -- were great for morale ... especially in light of recent tensions.

We're told Big Willie did his research for the role, took a few pics ... then bounced.