Knut Avenstroup Haugen is a Norwegian video game composer best known for his work on Age of Conan: Hyborian Adventures. Born in Oslo, Haugen demonstrated a talent as a pianist from an early age while growing up in Kristiansand. As a piano scholar, he attended the Conservatoire at Agder from the age of 18 and took post-graduate studies at Utrecht. During his time in Holland, Haugen decided he didn't want to become a pianist and instead followed his dream of becoming a composer. He subsequently undertook a Masters at the University of Oslo in composition and musicology.

Haugen currently works full-time as a composer in Oslo. His extensive studies in harmony, orchestration, jazz, and modernist composition have allowed him to work in diverse roles. He has been commissioned to create a number of classical compositions. At the Oslo Opera Festival in 2007, Haugen composed a romantic piano concerto and an orchestra and choral piece set to a poem. These works were performed by the Oslo Symphony Orchestra under Sir Einar Steen-Nøkleberg. He has since offered a cycle of songs for tenor, harp, and string quartet set to poems by Henrik Wergeland.

Haugen was commissioned to create a short sample-scored for the video game Bubbins: The Green Monster in 2007. While the game has been indefinitely delayed, his experience on this project enabled him to tackle the score for Funcom's epic Age of Conan: Hyborian Adventures. He created a three and a half hour score featuring instrumental and vocal performances mixed with high quality samples from the Vienna Symphony Library. He was praised for the way he hybridised cultural influences to create a vibrant, emotional, and often barbaric fantasy score. He is likely to work on future game projects including Age of Conan's first expansion.