Colin Hanks is famous. Somewhat anyway. He is the co-star of a currently running TV series, The Good Guys. I don't know if it's any good or not. He had a short arc in Mad Men. He was in the movie The Great Buck Howard - where Tom Hanks played his father.
In many ways Colin Hanks is comparable to Mamie Gummer who has had a respectable career on stage and screen for several years. Unfortunately she is completely overshadowed by her mother, Meryl Streep.