She served as part of the Dutch resistance against the Nazis during World War II, was a movie actress for 40 years, and was devoted in the latter part of her life to humanitarian causes as a part of UNICEF. All this and yet the mystique surrounding Audrey Hepburn — who would have turned 90 this year, 25 years after she left us — lives on, inspiring new generations of fans via her renowned fashion style and memorable roles in such classic films as Roman Holiday, Breakfast at Tiffany’s, My Fair Lady and Wait Until Dark to name a few.

“The continuing fascination really is astonishing,” offers Victoria Loustalot, author of Living Like Audrey: Life Lessons from the Fairest Lady of All. “The thing that struck me first and foremost when I began researching her — which was a project that was brought to me rather than one I initiated — is I knew she was an icon, but I don’t think I had really understood how much of an icon she had been from the time she was in her early twenties and made Roman Holiday, which was kind of her breakout moment, to so many different generations. I think that is really significant. I’m in my early 30s and women in their 30s felt that way about her, but there were also women sort of coming up behind us in their 20s, and even their teens, who have a passion for her. I hadn’t really understood how beloved she was by her peers and by young women of her generation.”

Robert Matzen, author of Dutch Girl: Audrey Hepburn and World War II, admits to being “astonished” by the number of people who have asked him that particular question regarding Audrey’s enduring popularity. “I’m going to say it’s not only this timeless beauty and class that she had, but the way that she culminated her life with incredible charity work,” he muses. “You know, going into the field, to Somalia and a dozen places in 18 months … it was just crazy. How many countries and how many situations did she walk into on behalf of UNICEF? I think that cemented her legend, what she did in the last years of her life.”

For much more on Audrey Hepburn, please scroll down below.

And now you can also listen to our podcast interview with Robert Matzen.