To say that Leslie Feist was, at any point, our little secret would be a stretch. After 2004’s breakthrough, Let It Die, Feist’s follow-up album, The Reminder, launched her into the mainstream. She toured Europe and North America for nine months straight. She even performed on Conan and Letterman. But it turned out that the girl who managed to link Toronto’s snowballing music scene with the chanteuse tradition of Paris was just getting started.

Then in early autumn came the very big, incredibly lucky moment: The tastemakers at Apple picked her innocently catchy single “1234” to accompany a commercial for a new iPod.

That’s when things took off. Downloads spiked. The song skipped up the charts. And Vanity Fair included Feist alongside Joni Mitchell and the Guthries in a story on folk legends. Countless concerts and magazine shoots later, she was burned out. She cancelled the Brazilian leg of her tour and declined appearances on Today and The View. It was a well-deserved break. By that point, even your grandma knew the song’s bouncy lyrics by heart.

Feist is still recovering when we meet up with her, the day before her Saturday Night Live appearance in November. She is rehearsing for the show and is surprised at how “civilized it is compared to Letterman, where they need you there at the crack of dawn.” She says she is skeptical about all the attention: “I’m grateful it’s happening, but at the same time it’s unhealthy to see yourself squished flat in a magazine or on TV.” What bothers her most is the possibility that her popularity might be getting our of her control. Not that she doesn’t try: She had her label take down the website for The Reminder after she decided it was too “robotic.” “I still want everything that is an extension of me to feel true,” she explains.

This is what is most alluring about Feist and, surely, a factor in her quick rise: the clear sense that her persona is entirely authentic. When she sings of betrayal or distant lovers, her voice – with its peculiarly husky timbre – seems so full of emotion that it could crack. Like Nina Simone (Feist covers her “See-Line Woman,”), she knows the heights of romance – and the follies.

The night she appears on SNL there are cameo appearances by Barack Obama and Bono, but it’s Feist who steals the show. She performs “1234,” of course. But when she returns to the stage, she sings the romping “I Feel It All.” For those three brilliant, breathtaking minutes, you better believe she does.