It's all quite simple

mademoisellececilia:

Keira Knightley and Karl Lagerfeld on the set of Once Upon a Time…(x)

“Do it your way, huh?” Lagerfeld told the two actresses as they rehearsed their lines.
While every detail of the short film was worked out in his head, Lagerfeld explained that he encourages some improvisation with the dialogue for a more natural effect. “Keira can deliver her lines easier than the others,” he said, referencing the fact that many of the cast members are models rather than professional actors.

For Knightley, who initially thought it might be a silent movie, discovering her lines moments before the cameras rolled was a first.“Karl Lagerfeld stage manages the actor in a truly direct way”, she marveled.