Carl Gustaf Hammarsten (born 2 September 1967) is a Swedish film, television and theatre actor. He is internationally known for his role in Brüno (2009) as the title character's sidekick and gay lover.
He has appeared in more than ten films, starting with a small role in The Best Intentions (1992) directed by Bille August. He is best known for his appearance in Together (2000) directed by Lukas Moodysson. He has a small role in the movie Old (2021)
Hammarsten made his international film début in Brüno (2009) as Lutz, the title character's sidekick. He has since appeared as the young Harald in David Fincher's remake of The Girl with the Dragon Tattoo, Kursk, Old, Lord of Chaos and Stockholm.
In Swedish television he became known through the comedy show Cleo. He has also made numerous appearances in television programs. He appeared in the first episode of Crimes of Passion. Since 2013 he acts in the series Fröken Frimans krig.