Christopher Guest is a British-American actor, director, and writer known for his work in mockumentary films. He gained fame for his roles in movies like This Is Spinal Tap, which he co-wrote and starred in, showcasing his talent for blending humor with music. Guest often collaborates with a group of actors, including Catherine O'Hara and Eugene Levy, to create unique comedic films. In addition to acting, Guest has directed several acclaimed mockumentaries, such as Best in Show and A Mighty Wind. His films often explore quirky subcultures and feature improvisational comedy, allowing actors to showcase their talents in a spontaneous way.