Will Smith's firstborn son co-starred with him in the "Just the Two of Us" music video -- but we hadn't seen much of Trey Smith since then ... until our camera guy bumped into him in the Valley.Trey's not nearly as famous as his dad -- or his…
TMZ Staff, TMZ
Thu, 07/10/2014 - 7:00pm
Will Smith's firstborn son co-starred with him in the "Just the Two of Us" music video -- but we hadn't seen much of Trey Smith since then ... until our camera guy bumped into him in the Valley.Trey's not nearly as famous as his dad -- or his…