IMHPO. I believe it's important not mistake a "role model" with a mentor. Just remember that it's all subjective too.
To really understand things, a role model is anyone that serves as an example and whose behavior is emulated by others. All mentors can be role models but not all role models serve as mentors. I have to believe that a mentor would be someone you have had direct personal contact with and this person(s) has taken on the responsibility or role as a personal adviser, someone who imparts wisdom and has a vested interest with you and in your successes.
I guess the line between role model and mentor could easily be blurred. Yet I believe if you have never met the person, they can only serve as a role model if your only contact has been through a book, article or other form of media.