Marion Cotillard has said that after more than 80 takes on her new film Two Days, One Night, she would insist on doing more.
The French beauty, wearing a fitted black Dior cocktail dress with a jewelled floral embellishment, joined director brothers Jean-Pierre and Luc Dardenne for the premiere of the movie at London's Somerset House.
Oscar-winner Marion stars as Sandra, a married mother-of-two with depression, who has just two days to convince her colleagues to give up their annual bonuses for her to be able to keep her job.
The Dardenne brothers insisted on doing multiple takes, of sequences sometimes over ten minutes long, and if a mistake was made at the end the actress would have to start from the beginning again.
But she said: "It was never under 40 takes, it was pretty much around 40,50 takes. They give you an energy, I mean I was never tired, even when we had done like ninety takes, and even sometimes I asked for more.
"Because we had ideas, and I did ask for more.
"They just create this atmosphere of work, and that's where I find my freedom. When I know I'm going to be able to work and explore thoroughly, that's when I feel totally free to give what I have to give."
The Inception star will next be seen playing Lady Macbeth in Shakespeare's tragedy opposite Michael Fassbender.
She said: "It's kind of hard to talk about it. We finished the movie in March and I still feel it was yesterday."
The screening marked the opening of the Film4 Summer Screen season at Somerset House.
Summer Screen will run until August 20, and includes the UK premieres of 20,000 Days On Earth, a drama documentary that follows a day in the life of musician Nick Cave, and vampire mockumentary What We Do In The Shadows.
Rosemary's Baby, Annie Hall and Ghostbusters are among the classic films being shown under the stars at the open-air festival.
Two Days, One Night opens in UK cinemas on Friday, August 22.