Nikki Sixx is an American musician, songwriter, and author, best known as the bassist and primary songwriter for the rock band Mötley Crüe. Born on December 11, 1958, in San Jose, California, he co-founded the band in 1981, which became famous for its energetic performances and hits like "Girls, Girls, Girls" and "Kickstart My Heart." In addition to his work with Mötley Crüe, Sixx has been involved in other musical projects, including the band Sixx:A.M.. He is also an accomplished author, having written several books, including his memoir, "The Heroin Diaries," which details his struggles with addiction and recovery.