U.S. actress Kristen Stewart, best known as Bella in the hit Twilight franchise, ditches her image as a wholesome, reserved teenager to play a foul-mouthed, pot-smoking prostitute in Welcome to the Rileys.
The movie, which is at the Berlin film festival without its two biggest stars - Stewart and The Sopranos lead James Gandolfini - has found a distributor for the key U.S. market and will hit cinemas in the autumn.
Director Jake Scott, son of Ridley, said he first considered Stewart for the part of Mallory when Sean Penn recommended her on the strength of her performance in his movie Into the Wild.
Stewart, 19, has become a teen idol for her part in the two Twilight movies released so far, and her involvement in Welcome to the Rileys is likely to be a major boost for a low-budget, independently produced film.
"We shot this in 2008, so Twilight came out when we'd wrapped," Scott told reporters in Berlin on Monday. "I saw her in Into the Wild. We got lucky."
Stewart plays Mallory, a down-and-out teenaged stripper and prostitute in New Orleans who Doug Riley, played by Gandolfini, takes under his protective wing.
We quickly learn that his affection for the girl is driven by a desire to find a surrogate for his own daughter, who died in a car crash aged 15.
Riley's wife, played by Melissa Leo, overcomes her grief and paranoia and drives from their home to see him, and she quickly agrees to play the role of mother in the new "family".
"As a director I was attracted to it (the story) because I'm a father and I made a film really about fatherhood," said Scott.
While reviews have criticised the plot for being contrived and cliched, the three main performances have drawn praise and underlined Stewart's credentials outside the blockbuster world.
Co-producer Scott Bloom of Argonaut Pictures underlined how small films found it hard to get to movie theatres.
"This is the first film we actually produced," he said. "We put a fund together about two years ago and we were hesitant to get involved in a project like this because it is very challenging.
"It kind of goes against the normal way of thinking about things."
Another low-budget U.S. movie screened in Berlin on Monday, "Father of Invention", has yet to get a distributor, despite the fact that it stars two-time Oscar winner Kevin Spacey.
For director Scott, Welcome to the Rileys is his second feature and the first in a decade. "It took 10 years because no one would let me do a film," he said. "I tried really hard. I've literally been trying for 10 years to make a film. It was not for lack of trying.
"(Debut film) Plunkett & Macleane was really poorly received, I would say justifiably poorly received, and it was quite hard."