You saw Annie Lennox sing “I Put a Spell On You” at the Grammy Awards this week, and today, if you go to see the hotly-anticipated movie Fifty Shades of Grey, you’ll hear it, too: it’s the first song in the film. Annie’s not exactly a Fifty Shades fan, though, and says it’s a “fluke” that her song even ended up in the movie.

Speaking to Spin Magazine, Annie says she knows the movie’s director, Sam Taylor-Johnson, but when they asked her for a song for the movie – a different song – her reaction was, “I’m not really sure about that.” Still, she agreed to drop by the studio and talk to the filmmakers, and when she got there, she discovered that one of the editors had put “I Put a Spell On You” over the opening sequence, just to see how it would work, and everyone was pleasantly surprised.

“We all came in about a half a dozen of us in the room and it fit like a glove,” she tells Spin. “There was just a sort of a sharp intake of breath after he played it. Everybody said, ‘Well, that has to be it. That’s perfect.’ It was just a done deal, it was like, ‘Yes! That works.'”

However, Annie says she still wasn’t convinced it’d make the final cut. “Things change in film, so I wasn’t really expecting them to use it, and yeah, it’s there!” she adds. “You’ll see if you go to the film, it’s there at the very opening.” While she hasn’t seen the entire movie, she says she trusts that Taylor-Johnson has “done a very elegant job with it.”

As for her opinion on the Fifty Shades erotic novels on which the film is based, Annie tells Spin she’s never read them. “I wasn’t, interested in them, to be frank with you,” she explains. “Quite often when things are super popular, I kind of catch up with them years later. I kind of avoid that.”

“I Put a Spell On You” is on the Fifty Shades of Grey soundtrack album, in stores now, as well as on Annie’s current, Grammy-nominated album, Nostalgia.