My daughter reached out to her favorite very well known author while in high school. She sent him an email on a dare from a friend. To her surprise he actually responded. They became pen pals and he has helped/encouraged her to continue her world building. He has been very helpful, which I hear is not uncommon for this well known author when interacting with young, aspiring writers.

If you are going to do this, don't be a star struck fan. Treat them as people with interests outside writing, and contact them through established, published means. Don't be a creep.