Phillip (Sir Phillip Niles Argyle of Montréal) has blond hair and a blue shirt with a "P", while Terrance (Sir Terrance Henry Stoot from the "small village" of Toronto) has black hair and wears a red shirt with a "T". Like virtually all Canadians in South Park, they are geometrically-figured with small beady eyes and egg-shaped heads which flap up and down whenever they speak.
According to Terrance in "Canada on Strike", Phillip has diabetes, though this may have just been something to attempt to stop the strike that was going on before it gets out of hand. After fighting with Phillip in "Terrance and Phillip: Behind the Blow," Terrance becomes fat and stays that way for several episodes.