Dolph Lundgren -- aka Ivan Drago -- says he's down with the dude they cast as his son in "Creed 2" ... but tells TMZ Sports he's gotta make a big cosmetic change to sell the Drago look ...
BURN OFF HIS BODY HAIR.
FYI, Romanian bodybuilder/boxer Florian "Big Nasty" Munteanu was recently introduced as Drago's spawn ... and some 'Rocky' fans were complaining since he didn't really look like his pops.
But when we spotted Dolph in the Bev Hills, he told us Big Nasty's got the bod ... and is just a painful wax-sesh away from becoming a chip off the ol' block.
"Nice wax, a little bit of hair color ... I'm sure there's a way to adjust our looks."