Referencing a blueprint defined custom class..

[IrishKilter]

Header

TSubclassOf<ClassName> ClassPtr;

.cpp File

AClass::AClass(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
static ConstructorHelpers::FClassFinder<ClassName> ClassFinder(TEXT("**Path To File (IE: /Game/UI/HUD/BP_UI_HUD_PlayerInventory)**"));
	if (ClassFinder.Class)
		ClassPtr = ClassFinder.Class;
}