Joe Simpson -- That Topless Beach Dude Is My Meal Ticket

Jessica Simpson's dad is sticking tight to a 6'2" stud -- parading him all over Miami Beach -- and TMZ has learned it's all to make a buck.

The eye candy Joe Simpson photographed sprawling in the sand last weekend has a name ... it's Jonathan Keith, and he's a model Joe is taking under his wing.

A source connected to Joe tells us JK is fresh off the boat from Scotland, and Joe's been managing him for about 5 months.

We're told Joe and Jon are in Miami to book modeling gigs. So that whole scene on South Beach was just practice.

Nice pull, Joe.