Much of the scene where Andie crashes Ben's "boy's night" was improvised. Kate Hudson had the idea to toss the platter of veggies at the guys seated at the poker table. Donald Petrie, the director, knew she was going to do this, the actors in the scene were truly surprised.
The dress Andie wears to the Warren Advertising gala was designed around the 84-carat yellow diamond pendant which she wears at the gala. It was designed by fashion designer, Dina Bar-el, not the film's costume designer, Karen Patch.
Andie wears a Harry Winston diamond wreath necklace with an 84-carat yellow diamond pendant (called the "Isadora") attached, valued at approximately $5,280,000 and a pair of 5-carat radiant cut yellow diamond stud earrings worth approximately $125,000.
The Alexander Hamilton U.S. Customs House, in the financial district of New York City, NY was used for the Astor Museum of Art, where the Warren Advertising Agency hosts a gala in honor of the DeLauers.