Although he designed for many famous faces - Grace Kelly, Jackie Kennedy, the Duchess of Windsor, it was Audrey, his life long friend and platonic love affair who was his muse.
They met when she phoned him up to ask him to design the costumes for the movie Sabrina, and although he could not produce that many new outfits in the time frame, she took a look at his current collection and found many she would ultimately use. The one featured below, was designed and made specifically for her:
this website. The dress was just a strapless panel line with a fitted skirt, and the train was actually a separate piece that hung from the belt around the waist. The black beading was intricately done, and the black ruches made of silk organdy at the bottom of the dress measured about 10 metres in length!
Givenchy designed many outfits for Audrey's personal life as well as costumes for many of her films from then on including Funny Face (1957), Love In the Afternoon (1957), Breakfast at Tiffany's (1961), Paris When it Sizzles (1964), How to Steal a Million (1966), Charade (1963) and Love Among Thieves (1987). Audrey was also the face of his fragrance L'Interdit.
These videos encaptulates the relationship between Givenchy and Audrey.
(this one in French)