Adam was in Montecito Friday caressing his new pooch -- a fluffy Leonberger, a German-bred dog that will be enormous. Females get up to 140 lbs and dude dogs 170 lbs -- yes 170!!!

Check out the pup's paws ... you can see what's in store for the Levine family.

Aside from sheer size ... these dogs shed like crazy -- so much so, grooming them has become a cottage industry. There are even competitions for who can get the biggest hairballs.

BTW ... can't tell if it's a male or female ... it's a little shy in the pics!