The actress opens up about the botched surgery that stamped out her singing voice nearly 20 years ago

The hills are alive! As The Sound of Music turns 50, Julie Andrews and Christopher Plummer share their memories of making the classic movie. Subscribe now for instant access behind-the-scenes, only in PEOPLE.

It’s every singer’s nightmare. In 1997, Julie Andrews underwent surgery to remove noncancerous nodules on her vocal chords. When she awoke, the angelic soprano that delighted audiences in The Sound of Music, Mary Poppins and Victor/Victoria was gone.

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“If it had happened earlier, it would have been really devastating,” Andrews tells PEOPLE in the magazine’s new issue. “As it was, it was devastating.”

Now, nearly 20 years after the botched surgery, and 50 years after The Sound of Music made her a star, Andrews reveals that her vocal trauma forced her to develop other creative outlets. “For a while, I was in total denial,” but then “I had to do something.”

That “something,” was to pen dozens of books, including co-authoring the Dumpy the Dumptruck and The Very Fairy Princess children’s series with her daughter, Emma Walton Hamilton. “What I say in the [The Sound of Music] is true: a door closes and a window opens,” adds Andrews. Had she not lost her voice, “I would never have written this number of books. I would never have discovered that pleasure,” she says.

She also might not have made The Princess Diaries and Despicable Me, films that brought her to the attention of a new generation of audiences.

“I thought at the time [of the surgery,] my voice was what I am,” recalls Andrews. “But it seems it’s not all that I am.”