Diane Keaton was also one of a rare few screen legends whose unmistakable look influenced the roles she portrayed on camera, such as her titular character in Annie Hall. The costumes that she wore for the film—waistcoats, printed ties, and tailored trousers—primarily came from her own wardrobe and are among Hollywood's most iconic examples of great onscreen style. 

Keaton rarely wore colors, focusing her acute fashion style on the striking and apparently limitlessly interesting possibilities of black and white, playing with clashing prints and textures and accessories, and often topping her looks with one of her classic hats.

In more recent years, her extraordinary fashion sense captivated a new generation. She was celebrated at New York Fashion Weeks, attending shows for the designers whose work became associated with her wardrobe including Ralph Lauren and Thom Browne, and never stopped engaging with her own personal style.