Matthew Brandon Ross (born January 3, 1970) is an American actor and filmmaker. He is known for his roles as Alby Grant on the television series Big Love (2006–11) and Gavin Belson on Silicon Valley (2014–19), as well as his performances in the films The Last Days of Disco (1998), American Psycho (2000), and The Aviator (2004). He wrote and directed the 2016 comedy-drama film Captain Fantastic.