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Born Arianna Forster, the cause of her death was not released and no further details have been given. Lydon, who is married to Up's mother Nora, confirmed the news in a post on his website. "John and Nora have asked us to let everyone know that Nora's daughter Arianna (aka Ari-Up) died today after a serious illness," it read. "She will be sadly missed. Everyone at JohnLydon.com and PiLofficial.Com would like to pass on their heartfelt condolences to John, Nora and family. Rest in peace."
Ari Up and her dreads became the iconic image of one of the first all-girl punk bands. She formed the Slits in 1976 at the age of 14 and went on to release two albums, 1979's 'Cut' and 1981's 'Return of the Giant Slits.' They would disband shortly after, eventually reforming in 2005.
Watch The Slits video for 'So Tough' after the jump.