Yasiin Bey (born Dante Terrell Smith), previously and more commonly known by his stage name Mos Def, is an American rapper, singer, songwriter, and actor. He began his hip hop career in 1994, alongside his siblings in the short-lived rap group Urban Thermo Dynamics (UTD), after which they appeared on albums by Da Bush Babees and De La Soul. He subsequently formed the duo Black Star, alongside fellow Brooklyn-based rapper Talib Kweli, and in 1998 they released their eponymous debut album, featuring the singles "Definition" and "Respiration". He was featured on the roster of Rawkus Records and in 1999 released his solo debut, Black on Both Sides. His debut was followed by The New Danger (2004), True Magic (2006), and The Ecstatic (2009). The editors of About.com listed him as the 14th greatest rapper on their "50 Greatest Rappers of All Time" list. Some of his top hits include "Oh No", "Ms. Fat Booty" and "Mathematics". Prior to his career in music, Mos Def entered public life as a child actor with roles in television films, sitcoms, and theater. Since the early 2000s, he has appeared in the films Something the Lord Made, Next Day Air, The Hitchhiker's Guide to the Galaxy, 16 Blocks, Be Kind Rewind, The Italian Job, The Woodsman, Bamboozled, and Brown Sugar and in television series such as Dexter and House. He is also known as the host of Def Poetry Jam, which aired on HBO between 2002 and 2007. Mos Def has been vocal on several social and political causes, including police brutality, the idea of American exceptionalism and the status of African Americans.