Complex sentence: He is well known for his roles as guitarist Russell Hammond in "Almost Famous", Will Bloom in "Big Fish", Ashitaka in "Princess Mononoke" and perhaps his most famous role yet as Doctor Manhattan in the 2009 film "Watchmen".
Split into simpler sentences: 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 appeared as Doctor Manhattan in the 2009 film "Watchmen".