Willie Hugh Nelson (born April 29, 1933) is an American country musician. The critical success of the album Shotgun Willie (1973), combined with the critical and commercial success of Red Headed Stranger (1975) and Stardust (1978), made Nelson one of the most recognized artists in country music. He was one of the main figures of outlaw country, a subgenre of country music that developed in the late 1960s as a reaction to the conservative restrictions of the Nashville sound. Nelson has acted in over 30 films and co-authored several books. Nelson uses a variety of music styles to create his own distinctive blend of country music, a hybrid of jazz, pop, blues, rock and folk. His "unique sound", which uses a "relaxed, behind-the-beat singing style and gut-string guitar" and his "nasal voice and jazzy, off-center phrasing", has been responsible for his wide appeal, and has made him a "vital icon in country music", influencing the "new country, new traditionalist, and alternative country movements of the 1980s and 1990s".