William Gaither "Billy" Crudup ( born July 8, 1968) is an American actor of film and stage. He is well known for his roles as guitarist Russell Hammond in
Almost Famous, Will Bloom in
Big Fish, and Ashitaka in Princess Mononoke. He also starred in the 2007 romantic comedy film
Dedication, alongside Mandy Moore. In 2009, he appeared as Doctor Manhattan in the film
Watchmen and as J. Edgar Hoover in the film Public Enemies.