"Sex Pistols frontman John Lydon is mourning the death of his step-daughter Ari Up, herself a punk star.
Up - whose real name was Arianna Forster - was a member of the all-girl punk-reggae act The Slits, who reformed occasionally to tour.
She died on Wednesday from a "serious illness" and the death was announced on Lydon's website.
Up, 48, formed the band with Paloma Romero - better known as Palmolive - with Viv Albertine also featuring in the line-up.
They were part of a music scene which was at the centre of the punk explosion and were most famously known for tracks such Typical Girls and their cover of Heard It Through The Grapevine.
Lydon is married to Up's mother Nora Forster - a German publishing heiress - and they have been together for three decades.
Announcing the death on Johnlydon.com, a statement reads: "John and Nora have asked us to let everyone know that Nora's daughter Arianna (aka Ari-Up) died today (Wednesday, October 20th) after a serious illness. She will be sadly missed."
The cover of The Slits debut album - in which Up and her bandmates were photographed topless and smeared with mud - became an enduring punk image.
Dreadlocked Up, who was born in Munich, was just 14 when she originally formed the group."
Condolences to the Lydons.