Rob Kardashian Weight Loss: In the Drop Zone

The only thing more obvious than Rob Kardashian's confidence coming back ... is that Blac Chyna does a body good!

Rob made a rare public appearance with his GF on Tuesday -- looks like the couple was out in L.A. running errands in the tight confines of her Audi R8 sports coupe. As we've reported, Chyna got her man back in the gym where he's been working out regularly and dropping the lbs.