A child star who started acting in TV roles alongside Bill Cosby at the age of 14, Mos Def steadily built a film career, while becoming one of the most acclaimed rappers of his generation. He formed the group Urban Thermo Dynamics with his brother and sister but started making waves as a solo guest on tracks by De La Soul and Bush Babees, before teaming up with Talib Kweli for the acclaimed album Mos Def & Talib Kweli Are Black Star (1998). His debut Black On Both Sides (1999) showed a socially conscious style, not afraid to delve into genres such as jazz, blues and rock in the mould of A Tribe Called Quest or Gil Scott Heron; but his attentions turned back to acting with roles in the films Monster's Ball, The Italian Job and Hitchhikers Guide To The Galaxy. Led by the single Sex, Love & Money, he returned with the successful US Number 5 album The New Danger (2004) and was nominated for a Grammy Award for fourth album The Ecstatic (2009). He has collaborated with Gorillaz, Black Keys and DJ Shadow and remains one of the most literate and politically active voices in hip hop.