How can someone whom you have not sought physical advice from, be your mentor? The term you are looking for is either idol or inspirational.
I have to agree with 47 there. A mentor you have a relationship with. Inspirations, heros, idols, etc, you don't usually. There are exceptions to the later rule, but not the former.
I've personally been inspired by a few folks...Richard Garriott (Creator of the Ultima series), Gen. James Longstreet (CSA), and Gen. George S. Patton (USA) to name 3. Never met em though. My mentors...couple of my high school teachers, 2 coworkers, and 2 of my martial arts instructors.