Sienna to play the threesome-loving siren who made London swing in the 1960s

The actress, who seems to be making movies back-to-back these days, will play Louise Ferrier, a famous name four decades ago but a mere footnote now.

Louise was the girlfriend of Richard Neville, the editor and co-founder of the underground magazine Oz, which published first in Sydney, then in London.

The couple took the hippy-trippy trail from their native Australia and landed at Southampton in 1966.

It's said that Louise, an artist and writer, was the "siren" who drew Neville to our shores.

The couple were part of what was once quaintly known as the "scene".

They cut a swathe through literary, fashion, arty and cinephile London, puffing (but not inhaling) the occasional spliff along the way.

Maureen Cleave, a celebrated chronicler of Sixties London, wrote at the time that Louise was game for anything: "twosomes, threesomes". Indeed, she and Jenny Kee (a renowned designer) posed naked on the cover of the December 1968 issue of Oz.

Director Beeban Kidron will explore all this and much more in her film Hippie Hippie Shake, written by Lee Hall (author of movie and stage hit Billy Elliot) and based on memoirs written by Neville.

Cillian Murphy will portray Neville, who was one of the three defendants in the landmark Oz magazine obscenity Old Bailey trial in 1971.

The trio, James Anderson, Felix Dennis and Neville, were found guilty but later had their convictions and sentences quashed by the court of appeal.

The movie begins filming in September for Working Title with Max Minghella and Emma Booth in the cast.

Interestingly, Sienna met up with Cillian at the Groucho Club in Soho this week, along with Keira Knightley and Matthew Rhys, to prepare for the film The Best Year Of Our Lives, which is about to shoot in Wales.

Louise and Jenny Kee (a renowned designer) posed naked on the cover of the December 1968 issue of Oz