Universal Pictures

Andy and Barbara Muschietti were the victims of their own success. The brother-sister filmmaking team made a big splash internationally with their 2008 horror short Mamá (Andy directed; Barbara produced; both co-wrote). The three minute “style exercise” (Andy’s words), about a pair of young sisters pursued by a supernatural entity they call “Mama,” was meant to drum up interest in another full-length script of theirs.

Instead, producers wanted to know who “Mama” was and why the girls called her that.

Says Andy: “They were more interested in seeing what happened to the girls...”

 “...Than in reading our other script,” finishes Barbara.

Three years later, in October 2011, the Argentinean-born siblings find themselves sitting in a conference room at the newly-opened Pinewood Toronto Studios, talking to North American genre press about the full-length version of Mama they are three weeks into filming. Visionary director Guillermo Del Toro (Pan’s Labyrinth, upcoming Pacific Rim) has signed on as their executive producer (and Andy’s unofficial mentor), Universal Studios is putting up the budget and releasing the film in America (eOne has those honours in Canada), and Oscar nominee Jessica Chastain (The Help) is heading the cast of this Spanish-Canadian co-production.

Not bad for first-time filmmakers, although neither Andy nor Barbara are novices. Both had worked in film in various capacities, in various countries, for years before deciding to open their own company a decade ago in Barcelona to make television commercials (Andy directs, Barbara produces.)

But all that experience behind the camera did not necessarily prepare Andy for the marathon which is feature filmmaking.

“I’m not ready yet,” he says, only half-joking. “I guess it’s just something that happens. I guess I was more ready to make a film ten years ago, when I thought it was easier. And now that I’m doing it, I’m encountering all the little surprises and obstacles that a long-run have (sic).”

Mama stars Chastain as Annabelle, a childless young woman forced to care for her boyfriend’s (Nikolaj Coster-Waldau, Game of Thrones) two young nieces (Megan Charpentier and Isabelle Nélisse). The girls have been found after five years of living feral in the woods. How they survived is a mystery, although it soon becomes clear to Annabelle that a malevolent spirit with a strong maternal instinct has come to reclaim them and will not brook anyone – including Annabelle – trying to usurp her place.

Producer J. Miles Dale (upcoming Carrie remake) calls the casting of the girls a “tricky process,” with open casting calls held in Montreal, Vancouver, and Toronto. “We looked in the woods for feral children,” he jokes.

“It was a tough process because we knew they were kind of the key to the movie. The believability of these kids and [the fact] that they were raised by a spirit in the woods from a very young age... the movie was going to hang on that.”

The ‘casting’ of Mama was equally difficult. Initially, Andy thought the creature would have to be computer-generated to accommodate everything he wanted the character to do physically, but “as cool as the CG are (sic), there’s always something that tells you that it’s CG.”

Instead, the Muschiettis cast Javier Botet, an incredibly thin Spanish actor best known for playing the infected creature at the climax of the 2007 Spanish horror film [Rec] and its sequels, in the role.

“I thought it was CG, that character, because the proportions were not real,” says Andy. “You see this thing, and it’s swaying and the head is like that,” twisting his head into an awkward position.

Botet plays the role with facial and breast prosthetics, as well as finger extensions. But Mama is then brought to life – pardon the pun – by CG that tweaks her movement and colouring. Visual effects supervisor Ed Taylor is especially proud of Mama’s hair, which he calls a “character” in and of itself.

“That’s the task,” he says in a separate interview, “just trying to bring it to life and make it not look like a passive entity.”

Perhaps the most interesting element of Mama, however, is Chastain. Best known for her dramatic roles, including her current hit, Zero Dark Thirty, Mama is her first horror film. The Muschiettis cast Chastain primarily based on an iTunes trailer for The Debt, a movie in which she plays an Israeli secret agent. Chastain had just broken out at Cannes in May 2011 thanks to her performance in Terrence Malick’s The Tree of Life, and Mama was one of the first scripts she received in the wake of that first wave of publicity. Chastain expressed interest, and the siblings scheduled a Skype meeting with the suddenly hot actress that June, which they quickly scrubbed a day beforehand in favour of a two-hour face-to-face in Los Angeles.

“She’s insanely good, and insanely nice and helpful,” Barbara says, “and we thank our lucky stars every day.”

“There’s something about her that worked for me,” says Andy. “The character has an arc, and at the beginning of that arc she should not only be like an unlikely person, a reluctant hero, but she should be distant and not empathetic to the audience, and I saw her like that. She can be really distant. She has these features; she barely has eyebrows.”

There is some giggling amongst both the journalists and his sister at this remark.

“I wouldn’t say it if I didn’t think it wasn’t beautiful,” he insists. “She has, like, a porcelain thing going on there. And when I saw Jolene [her 2008 debut film], I saw all the emotional stages and moods she had. She was perfect.”

He pauses before adding: “And I love her nose.”