Paris dressing gown
Again, I’m not sure whether this is Edith Head’s work or Givenchy’s. Maybe Givenchy, now Sabrina has transformed? Sabrina wears this floor length dressing gown/house coat as she writes to her father before leaving Paris.
The front. Looks as if it’s made of a heavy silk, with wide stiff collar and turn back cuffs:
The back. There’s a lot of fabric in that skirt!