In the classic horror movies of the past, part of the fun arises from the "who’s-going-to-get-it-next?" effect. Harlin and his producers embraced this concept when it came to casting the motion picture.

Harlin offers, "We wanted to cast actors who were solid actors but not necessarily movie stars, as in the first ‘Alien’ movie, where nobody could have expected that Sigourney Weaver was going to survive. We really wanted to twist the story and put the audience in a position where they have no idea who is who, or what’s going to happen to these people. We want them to get to know these people as real, true flesh-and-blood characters rather than ‘movie stars.’"

Producer Goldsman echoes, "The advantage to casting actors, as opposed to stars, is that you may identify with a character who is suddenly taken away, leaving you feeling stranded. In ‘Alien,’ Tom Skerritt is so clearly the hero of the movie. When he’s killed you feel, as I’m sure Ripley [Sigourney Weaver] did, ‘my God, I’m left here without somebody to protect me.’"

But Harlin also wanted to cast Oscar-nominated actor (and star of the director’s "The Long Kiss Goodnight") Samuel L. Jackson ("a movie star who is an actor") in the movie, "…as a kind of anchor in the middle of the story. Once we had him, I went after the other cast members -- solid performers who could pull off these characters as real, emotional and as touching as possible. And meet the challenges of these incredibly physical roles."

Ludwig adds, "We really wanted to turn upside down the audience expectation that is inherent in this kind of a genre movie. Who’s gonna live and who’s gonna die?"

Jackson comments, "I looked forward to doing this picture, and it’s something different for me. I grew up watching monster movies. Even though this has a different kind of monster, it has all of the elements of films like ‘Frankenstein,’ ‘The Wolfman’ and of course ‘Jaws.’ But ‘Deep Blue Sea’ takes a lot of the conventions from previous films and turns them into something new. Inside it is a great monster movie plus a big chase movie, and I like being chased by things."

Jackson also adds, "You know, we’re the smartest thing on the planet theoretically, but when we get in the ocean, we’re out of our element, other things become a lot brighter and stronger and faster and more adept at dealing than we are. So we are put in a position of having to out-think the sharks, and that’s one of the appealing elements of this film."

The filmmakers had seen Thomas Jane in several acclaimed independent features and approached him to play shark wrangler Carter Blake. Jane says, "I knew it was going to be tough and challenging and worth every second. You get 40,000 gallons of water dumped on you. You get dragged around by a 8,000 pound shark. Fall off of ladders. Get burned. Drowned. Beaten. It’s been fun."

Jane continues, "When you read the script it says, ‘Carter steps outside.’ It doesn’t say, ‘Carter steps outside and gets hit by 4,000 gallons of water, and a helicopter hovers over his head in a swirling tropical thunderstorm at sea, and suddenly a two-ton shark just misses him by inches.’ But that’s what it’s like working on a Harlin picture." (The actor prepared for the role with an extensive workout regimen and admits, "Sometimes even that didn’t ready me for the work…but it’s been a great ride.")

Harlin had also caught English actress Saffron Burrows in several independent films, where she had done "serious character work." She herself says, "The physical elements were appealing, but it was the strength of McAlester’s character and her complexities that drew me to the role. I was interested in playing someone flawed, with so much that she really hasn’t acknowledged about herself. I love the fact that we’re not big action heroes. We’re normal people who are put in an extreme environment and then have to try to survive in a very human way."

As he had with millions of his fans, LL Cool J had connected with Harlin on a musical level at first. Then the director saw a couple of his films and cast him as Sherman "Preacher" Dudley, whom Cool J describes as "a cook who is a man of God, kind of like Robert Duvall’s ‘The Apostle’ meets Chef Boyardee -- then he has to run from underwater aliens. It’s great. They should put on the movie posters ‘Come on in…Keep your clothes on…Go home soaking.’"

The actor sees Deep Blue Sea as a personal "opportunity to grow. I’ve achieved a lot in music, but it’s time for a change, time to grow."

For the role of marine biologist Janice Higgins, filmmakers found Australian actress Jacqueline McKenzie, who had received the Australian equivalent of an Oscar for her film work in her native country. (Harlin explains, "I felt lucky that she wanted to do this type of film, but for her -- and for the other actors, too -- we had some interesting characters to offer. They wanted to come and play with the sharks, be in the water, do some intense physical work and work on characters different from what they had been doing previously.")

McKenzie says, "Back home, sharks are bad news. As a child, when I’d get a glass of water, my father would say, ‘If you put salt in there, there’ll be a fin swimming around inside of a minute.’ ‘Deep Blue Sea’ has actually been very good because I’ve been able to put to rest a few demons. I don’t usually bite my nails, but I did on this film."

Known for a wide range of roles in a series of independent and studio films, versatile actor Michael Rapaport was also approached (Harlin had produced a short film of Rapaport’s a few years before.) The actor brought a wry sense of humor to his role as Scoggins, a mathematical genius and the facility’s engineer.

Rapaport observes, "It’s been a great experience, getting to work on a Renny Harlin project. I’ve never done anything this size. It’s an entire world, this set. It’s huge and it’s real. What you see is what you get. That’s just the kind of dedication and involvement that Renny gets for his movies. Good people. Cool cast. Lots of water."

Fellow Scandinavian Stellan Skarsgård [Harlin is Finnish, Skarsgård, Swedish] was hired to play researcher Jim Whitlock, and the actor notes, "I’ve always been interested in food, so it’s fabulous to be able to play it for once. It’s fun to be working with Renny -- he’ll throw a line at me in Swedish every now and then, which is hysterical, because he has this terrible Finnish accent. He told me that there would be real sharks in the movie, which there are, but the sharks they created are incredible and they’re better paid than I am…I should have been a shark. But it’s great to be on such a big show; it attracted the boy in me."

"The ensemble cast is almost too good to be true," concludes Harlin, "and I do warn the actors when I cast my movies. I say, ‘Have you seen any of my movies before? You do realize that it was so-and-so climbing that mountain, and it was so-and-so underwater in that scene.’ And I try to paint the grimmest possible picture and say, ‘It’s going to be tough. It’s going to be physical. But it’s also going to be a lot of fun, and you’ll definitely get to do something that you haven’t done before.’ It’s an adventure on both sides of the camera."