TORONTO -- Having star power in a film is often a director's dream, but for Quebec's Philippe Falardeau, putting a celebrity face on "The Good Lie" posed a challenge.

Oscar winner Reese Witherspoon stars in the fact-based drama as a Kansas City employment agency counsellor who helps four Sudanese civil-war refugees find jobs and acclimate to North American culture.

Arnold Oceng, Ger Duany, Emmanuel Jal and Kuoth Wiel play the refugees, who experience culture shock and loss and loneliness in their new home.

The story that's making its world premiere at the Toronto International Film Festival is more about Sudan's Lost Boys and their harrowing journey during the civil war of 1983-2005 than about Witherspoon's character, and Falardeau had to find a way to reconcile those elements.

"My concern was, 'OK, because she only appears after half an hour, is this going to be, 'Whoa, all of a sudden we're landing in Hollywood'?" he said in an interview.

"That was my concern, artistically: 'How do I do that?' Having Reese's hair dyed brown was one way to do this. It's not the Reese Witherspoon that we're used to, because she's normally like platinum blond. ... But I think her work as an artist does that very well.

"I think she understood her role in that film. Warner Brothers doesn't. She's on the poster."

Yes, Witherspoon's smiling face is at the top of "The Good Lie" poster above an image of the refugees walking through a sunny African field. She's also featured prominently in the trailer for the project that's written by Margaret Nagle and marks Falardeau's first English-language film.

When asked about such marketing, Falardeau said he couldn't comment.

"I've told what I've had to say to Warner Brothers about that. For them, the advantages of that outweighs the disadvantages of that."

Ultimately Falardeau is "grateful" for the studio's role, though, he said.

"Today my message is, the story of the Lost Boys is worth sending out in the world and Warner Brothers can certainly do that at a scale that I couldn't have with my local distributor in Quebec, if the film had been done just in Quebec."

Falardeau, whose 2011 film "Monsieur Lazhar" was nominated for an Oscar for best foreign-language film, said he's been interested in Sudan ever since he filmed a documentary there in 1994.

He always knew a celebrity would star in the film and he chose Reese because the Louisiana native had the right "southern touch" and the range to be "kind of edgy at the beginning and ... transform into being this luminous person who connects with these immigrants."

"And also, when she came onboard, the film was pre-sold in 50 countries -- after she came onboard before a single shot was made -- and that meant that we were going to be able to make the film," said the Hull, Que., native, whose other films include "Congorama" and "It's Not Me, I Swear!"

"So for all these reasons, I think she was a very, very good choice. And Reese, on the set you understand very quickly why these people are stars, and I mean that in a good way. It's because you look at the framed camera and then she illuminates the frame. She has charisma, and charisma is something that cannot be taught or learned, and she is such a pro. You give her like five different directions at the same time and she will integrate them very, very quickly."

"It was fascinating" to work with Witherspoon, added Falardeau.

"It's very special for a star of her status to say 'yes' to a character which is really a secondary character," he said. "She's not the main character in this film. She's definitely servicing the story and from the beginning she knew that and I raise my hat to her for that."