On a sunny Saint Patrick's Day, cast and crew members of The Host, gathered at the Four Seasons Hotel in Beverly Hills to discuss the film. Entertainment Affair sat down with cast members Saoirse Ronan, Diane Kruger, and director Andrew Niccol. Check out highlights from the day below.

What if everything you love was taken from you in the blink of an eye? The Host is the next epic love story from the creator of the Twilight Saga, worldwide bestselling author, Stephenie Meyer. When an unseen enemy threatens mankind by taking over their bodies and erasing their memories, Melanie Stryder (Saoirse Ronan) will risk everything to protect the people she cares most about — Jared (Max Irons), Ian (Jake Abel), her brother Jamie (Chandler Canterbury) and her Uncle Jeb (William Hurt), proving that love can conquer all in a dangerous new world.

Saoirse Ronan was 13 years old when she earned an Oscar nomination for her critically acclaimed starring performance in Joe Wright’s Atonement. Ronan plays Melanie, one of the few surviving humans hiding out from aliens who have taken over the bodies of the rest of the race. After getting caught and being implanted with an alien being, Melanie forces her host body (now occupied by a being that comes to be known as Wanda) to return to her people, who are hiding out in New Mexico caves.

Is it difficult when you’re playing essentially two characters and you’re not seeing one for a lot of the movie and it’s really two different characters?
Saoirse Ronan: It wasn’t too difficult because they’re so different, the two of them. I mean, it’s very much set out in the book and in the script who these characters are and what they’re traits are, and I think it’s great that Melanie is so feisty and has such a mouth on her. She’s a real fighter. She’s very, very human and Wanda isn’t. She’s very kind of serene and positive about things, always keeps her composure.

Ronan admits playing two characters - one represented by voiceover within her body and the other, the more soft-spoken alien invader - was tricky. In order to achieve a believable performance, production decided that she would pre-record the dialogue of the inner voice and then wear an earpiece during the scenes.

How do you plot out leaving in enough time for the voiceover lines when you’re having conversations with yourself?
Saoirse Ronan: I think a lot of it was down to the sound department, because they would sort of operate when the lines were being fed to me. So no one on set could hear what was being said into my earwig that I had, but they would kind of control it. I think between them and Andrew… I don’t even know because I’d never be looking in that direction, but I think Andrew might have cued them to give me the next line. But yeah, that was a big question for me when I was going into it was how we were going to do this. How were we going to cue it? Were they going to have someone on set? We were trying to figure that out. But it worked out a lot better, I think, than any of us anticipated.

Andrew Niccol directed and wrote the screenplay for The Host. This is the first film that he has wrote the script based off a novel. He had a massive 600 page novel with a set story and ideas within to construct The Host.

How do you find that spine in a book as massive as The Host to adapt it into a screenplay?
Andrew Niccol: I’d never adapted a novel before, much less one that is 650 pages that I have to get down to 120. I remember getting it down to 200 and change, and went, “This can’t be done.” Eventually it got down there. I used tricks where I would make composite characters. I’d repurpose dialogue from one into another.

Having been through the adaptation process several times before, book author Stephenie Meyer came to the table with strong opinions about what the final script should look like.

Collaborating with Stephenie, how was that dynamic?
Andrew Niccol: Like I said, I’ve never adapted anything before, so I had no idea what to expect. I was a little anxious because she’s had so much success, it would be easy for her to not be normal. But she turned out to be really down to Earth. She was very soul like, in many ways because she would be very agreeable even if she disagreed. 

Another central character of The Host is the Seeker, a Soul who tracks humans and inserts other Souls into their bodies. Played by Diane Kruger, this particular Seeker is a bit of an anomaly, lacking the serenity and detachment of her peers. Tormented and driven, she becomes obsessed with unlocking Melanie’s memories and discovering the whereabouts of her surviving loved ones.

Diane, this is actually your first time playing a bad person right?
Diane Kruger: Well the jury’s still out if she’s bad or not, right? That’s what I thought was interesting actually. Like who’s actually the bad person, the human or the alien, right? It was interesting to be pleasantly terrifying. I love the ark. I thought it was an interesting character to play.

Meyer is currently in the process of penning a sequel to The Host.

Are you prepared for a franchise? Are you ready to get back and do another one?
Saoirse Ronan: I mean, if the script was right. I think that’s always the most important thing. I wouldn’t just want to do a sequel just for the sake of it, you know? If the script is good enough and the story is strong enough to carry on, then yeah. It would be great to carry on.
Andrew Niccol: Yeah, I was drawn to the story and I would love to keep working with Saoirse. Stephenie’s looking at it thinking, “Maybe I’ll change the second book because of the performance.” It’s that strange situation where the movie might be leading the novel because of her performance… it’s so startling. She’s a bit of a vault. Stephenie won’t tell me what’s going on in the second book. But, it’s supposed to be a trilogy.

The Host hits theaters March 29