Hepburn would go on to score an Oscar nomination for Breakfast at Tiffany's. And ironically enough, she and MacLaine would costar in MacLaine's follow-up to The Apartment and Hepburn's very next film, 1961's The Children's Hour. In the book, MacLaine says she "adored" working with Hepburn.

Shirley MacLaine nearly starred in Breakfast at Tiffany’s — and still has “never” seen the 1961 rom-com. In the Terms of Endearment star’s new book The Wall of Life: Pictures and Stories from This Marvelous Lifetime,