Let us start this one from the very beginning: 'Factory Girl', Sienna Miller's latest movie got such bad reviews at private screening that they had to go back on the set and re-shoot part of it. The movie, telling the story of Andy Warhol and of his muse, Edie Sedgwick, was entirely shot in Pittsburgh (you know, that town that Sienna called 'S**ttsburgh').

The point is that, besides the bad publicity that Miller's antics generated and the bad reviews from the critics, there is also a lawsuit pending against it, filed by legendary singer Bob Dylan, who is not at all pleased with the way he is being portrayed in it, meaning, as the killer of Edie.

So, the main star of 'Factory Girl', Sienna Miller, probably felt the need to do something to shake off the heat she and her movie have been getting from the press. And what does she do? She talks about sex, as it always happens in such cases.

When she was asked about a very explicit sex scene that appears halfway through the film, Sienna tried to explain the reporters that it was not something that the producers just put in for the sake of doing it, but completely necessary to the plot. The British actress explained that the whole segment was considered from the '60s perspective, when sex was very much a central point in rockers' lives.

Sienna is not worried about the public's reaction to it, but confesses that she is rather afraid of what her father might think when he will see her getting hot and heavy in front of the cameras. 'We wanted to make it realistic and I watched it thinking, "Oh my God, my dad's going to see it!". And that was going through my head. But it was relevant to the story in that it's a movie about the 1960s, and sex and drugs and rock and roll were a big part of that.'

'We didn't want to hold back because it is a real film and it is a gritty film and there was a lot of shocking things and it wouldn't fit in the film if we had an unrealistic sex scene. It was always a bit uncomfortable but I think it was relevant to the story.', Miller said in a recent interview.

Well, probably she should rest assured about what her father will think about her. If he has seen her topless in 'Alfie' and in 'Vanity Fair' and did not object to it, then she's out of the woods for playing 'mommy and daddy' in front of the cameras.