Ariane Daniela Forster, known by her stage name Ari Up, was a German vocalist best known as a member of the English post-punk band The Slits. In 1976, at the age of 14, Up formed the Slits with drummer Palmolive. Soon after the Slits were touring as the opening act for the Clash. Ari Up's love of reggae led the Slits into a "jungly" dub style. She was the most flamboyant member of the group, becoming known for her wild hair and stage outfits. She can be seen briefly in the film "Rude Boy" (1980), associating with the Clash backstage. Her 1977 performances with the Slits are featured in "The Punk Rock Movie" (1978), a documentary release of various punk group club performances, principally at The Roxy. The Slits disbanded in 1981. Ari Up and Tessa Pollitt reformed the band with new members in 2005, as Viv Albertine was unwilling to rejoin, and in 2006 released the EP Revenge of the Killer Slits. In 2008, Ari Up was diagnosed with breast cancer. On 20 October 2010, Ari Up died in Los Angeles, aged 48.