Sienna Miller plays Andy Warhol's famous muse, Edie Sedgwick

Sienna Miller has been in the spotlight recently - unfortunately, not for her acting, but for her relationships; the British actress has had an on again/off again relationship with Jude Law.

What's interesting is the person she plays in her new movie went through that very thing in the 1960's. In Factory Girl, Sienna Miller is Edie Sedgwick, Andy Warhol's first real muse. She became the party girl, who wanted to get into the 'scene,' but turned to drugs and eventually died of an overdose at age 28. Guy Pearce plays Andy.

Movieweb sat down with Sienna to talk about portraying such an amazing icon. Check out what she had to say:

What did you think of Edie's fashion sense? Did you get to keep any of the clothes?

Sienna Miller: I haven't gotten to keep any of the clothes yet; that's something I'm still working on. But, I love '60's style; she had such a unique sense of style, and really accidentally came upon it. She used to do these jazz/ballet work-outs, and she'd wear her leotards with her black tights, and then she couldn't be bothered to change, so she'd just put a coat over it, and it caught on and became this huge trend. It was sort of an inadvertent thing that happened. But, she had extraordinary clothes, beautiful clothes.

What kind of research did you do for this project?

Sienna Miller: I researched it for about a year; I read every book there was to read, and watched all of the films I could get my hands on. Actually, Guy Pearce and I went down to the museum in Pittsburgh, the Warhol Museum, and they let us into an archive room where they had different movies that people haven't seen, so we watched them. The thing about that era was that it was so well documented; everyone recorded everyone doing everything. So, there are just normal conversations between Edie and Andy, that he taped, that I had a CD of, to get her voice and her speech patterns. Then, I watched the way she danced, and I talked to her husband, her brother and her friends; you feel like this underground detective, going around. I went to Santa Barbara and saw her grave; there's the Sedgwick Reserve, which was the ranch she grew up in, and we found the entrance to it and climbed over and started running, to try and find the house. We got about a mile up, in the baking sun, and saw a sign that said, 'Mountain lions operate in this area,' and screamed and ran back out, so that didn't go so well. I spoke to her brother and he said he would personally take me on a tour around the house; I felt like I did everything I could have possibly done. I wanted to get to the stage where I was so familiar with her speech; she was very mannered - the way she smoked, the way she laughed, the way she moved. There's this book, Edie, by George Plimpton that has really detailed descriptions of her soul and her spirit. I didn't want it to be an imitation, so in order to emotionally connect to the material, you have to have done your homework enough that you feel comfortable with all the physicality; so when you're on set, you can let go of it and try to relate to the character, as much as possible.

Even though this was factually based, there seems to be a young, beautiful, tragic socialite in this generation; was there a modern twist to it?

Sienna Miller: It's all from the '60's; it was just a different thing then. She had such a specific voice, and it's such an old-fashioned Mayflower voice that I think it would have been confusing. And, I don't know who I would pick because I feel like she's so unique.

The first time you saw a picture of Edie, were you amazed at how much you looked like her?

Sienna Miller: I saw this photograph of her - I looked like her in the film because we had an amazing hair and make-up team. I saw this photograph of her that's a beautiful photograph, and I sort of fell in love with her, but I didn't think, 'Oh, G-d, it looks like me.' But, that was what drew me to the script; when I first got it, on the front page was a photo of her. And, she just has this magnetism and this luminescence and I think, like most people, I was very drawn to her - I saw resemblances, when I had the brown contacts and the beauty spot, and all of that.

Were you a fan of the art that Warhol was putting out in Factory Girl?

Sienna Miller: Yeah, certain parts of it; I think I like what it represents and, having really thought about it, I think he's an absolute genius. He was so ahead of his time, a lot of them were; with the way that he made his movies, putting the microphone in and making it real. He just had real people having real conversations - flash forward to us now, and our culture and our generation is obsessed with reality TV, but he was doing it in 1965. This man was just so forward thinking. And, the mockery of America, with the Campbell soup cans, throwing it back in its face - that's really interesting stuff. I prefer other artists, personally, but I really appreciate what he was doing; I wouldn't mind having a Marilyn in my house, to be honest.

What was the relationship that you and Guy Pearce had, on screen and off screen?

Sienna Miller: We actually went to New York in September and October, and we sat and went through the script with the director, George; we re-wrote some of our stuff and read it out loud, and we had a couple of nights where we'd put on the make-up and run around the hotel room, being them a bit. And then, I got back to London and Guy would call me, every now and then, going, 'Edie, it's Andy,' and we'd have this conversations, just because it was so much fun. We really adored each other; we got on really well, which is great, and I think important. But, on the days where the relationship wasn't so good, we wouldn't really talk; we did it as much as we could, and then, at the end of the day, we'd be like, 'I'm sorry, I love you.'

Would you stay in character the whole day?

Sienna Miller: We'd just been doing it for so long and, because it was a biopic and they are real people, I just felt, and I think he did too, a huge responsibility to do it as best we could. Also, we were having fun, and we were all in the clothes and we looked like them; we didn't do it religiously, but I think it's hard, if you're doing a scene where you have to hate each other, to be like, 'I love you.' You want to keep a little bit of tension.

Could you understand who Edie was?

Sienna Miller: I think that the most important thing was to psychologically try to understand why she was the way she was; from an exterior point of view, you see this girl who came from a very privileged background and had an education, and then went to New York and took too many drugs and died. People often say to me, 'Why? Who cares?' But, once you start delving into it, and you psychologically understand why she was freaking out so much; she had a really tortured background and a difficult upbringing. She was in and out of mental institutions, and had shock treatment at age 14, she was psychologically very disturbed; once you empathize and understand that, then it justifies why she was just running away from reality - reality, for her, most of her life, was quite a scary place. She was very layered, and I wanted to understand the vulnerability behind her; she looked so confident and aloof and beautiful, but underneath all of that, she was really fragile. I think that the vulnerability was something that I wanted to portray.

Was it painful for you to play Edie?

Sienna Miller: I wouldn't say it was painful; it was emotionally draining at times, certainly. The scene when I confront Warhol in the restaurant - that really emotional scene was my second day of shooting, and that was a little bit painful because I had just arrived and didn't know anyone. Sometimes, stuff like that happens and I had to make a decision whether to sink or swim, and you just have to go for it. So, it was emotionally challenging and also completely rewarding, from an acting point of view, because you feel a huge sense of achievement when you do get to a place, emotionally. I really loved it; I would be happy playing Edie, and no one else, for the rest of my life, cause she's just so interesting.

It's not painful to watch Sienna on screen; Factory Girl opens in theaters February 2nd, rated R.