Sienna Miller as Barbarella?
The rumour comes from The Daily Express (which brings a lot of rumours out) through WENN and Starpulse News Blog, so heavy rumour route then. That said you could actually see the fit of Miller in this role, whatever you think of how sexy she is...or her acting talent.
I think a big test for her will come when we get to see Factory Girl, apparently she is rather good in it and there are some positive comments coming out. Could this rumour pegging her as the lead contender for Barbarella be right? If you disagree, who could play a modern day sexually liberated, Austin Powers Fonda?