sunglasses Bradley Cooper car shorts dog puppy plaid shirt

Bradley Cooper is enjoying the dog days of summer ... he and his furry friend headed to a pre-July 4 Malibu party Sunday!

Cooper played it straight at the outdoor soiree, where others smoked cigars and drank around him. But Bradley kept hydrated with a water.

Guess his vice is just hangin' out with man's best friend!

Check out all the pics of Bradley in our gallery below!