To the delight of commuters, celebrated actress Maggie Gyllenhaal gave a surprise performance at Union Station Wednesday morning.

The 41-year-old star read an excerpt of Leo Tolstoy’s "Anna Karenina," which is a book she just recorded for audiobook app “Audible”.

“I love "Ana Karenina" — I love that book. It had a huge impact on me when I was younger and so when they came and asked me to do it, it was really compelling to me,” she told CTV News Toronto.

Audible, which launched 24 years ago, is a book-listening app owned by Amazon. It offers the world’s largest library of audiobooks — and adds thousands of new titles every month. Many of the readers are influencers or celebrities like Gyllenhaal.

“I think it’s interesting being a reader. You have an opportunity to say something to kind of like share something with the readers about what you’re feeling about the book,” said Gyllenhaal.

“It’s almost like an analysis of the book, so I wanted to offer that but also just step back enough so that people could have their own experience of the book.”

Gyllenhaal says reading the Tolstoy classic was a labor of love, one she worked on throughout the winter. The finished project is more than 35 hours long.

“Somebody asked me if I had listened back to it and I said — that’s too much of my life to have spent the time doing it and then to listen back,” she said with a laugh. “But I listened to a little with my husband because he’s never read the book, and we were on a long drive once, and I love it. I do. I feel really proud of it.”

She also says that not only will strangers be able to hear her narration of Anna Karenina, but so will generations of her own family, which she describes as “amazing.”

“After I did it someone pointed out to me that not just my children — and I read to my children a lot — I really love reading to my kids, actually; but my grandchildren or my great-grandchildren are going to be able to read Ana Karenina to them,” she said with a smile.

Gyllenhaal is also in Toronto to enjoy the Toronto International Film Festival. Her husband, actor Peter Sarsgaard, had a film open at the festival Tuesday night.