The most sexually explicit mainstream film of the decade could easily make or destroy a young actress’s career.

This morning Dakota Johnson slept with Seth Rogen. The weird thing is, Rogen doesn’t even know it. The two were seated next to each other on a 6 a.m. flight to Los Angeles from Vancouver, where Johnson was shooting some non-naughty bits of Fifty Shades of Grey. Johnson is a big fan of Rogen, but he didn’t recognize her.

Her hair is dyed from her natural blond to dark brown for Fifty Shades, making her look even younger than 24. Not that Rogen would have known who she was anyway. She tells the story with a goofball smile, its DNA lifted straight from her mom, Melanie Griffith. “I didn’t want to be like, ‘Hey, wake up, I’m Dakota.’ ”

Johnson should cherish her relative anonymity—relative is the right term when your grandmother is Hitchcock muse Tippi Hedren and your parents are Griffith, dad Don Johnson, and stepfather Antonio Banderas—while she still can. Fifty Shades of Grey unties itself in February 2015 with a built-in audience of 90 million mostly female readers, not to mention their panting male consorts, who will observe Johnson in various stages of love, bondage, and undress. Basically, Dakota Johnson is about to be revealed to Western civilization.

“I have no idea how it’s going to go,” says Johnson, widening her blue eyes. “I plan on handling it gracefully, to live my life as close as I can to how I do now.” She is exhausted from 14-hour workdays but musters a mischievous smirk. “I’m really a normal person.”

It’s true that Dakota Johnson has an appreciation for normal things, including a Red State love of skeet shootin’, and that her car of choice is a sensible, “mom-style” Mercedes. But here’s the hitch: If Dakota Johnson aspires to be normal, she is soon going to be screwed—and not in an Anastasia Steele kind of way.

Johnson tries to deflect the issue, claiming the real sexpot of Fifty Shades is costar Jamie Dornan—who will be the one saying lines like, “You’ve really got a taste for this, haven’t you, Miss Steele? You’re becoming insatiable”—but she’s the one who’ll play proxy for those millions of breathless fans who fantasize about being taken by his Christian Grey. It’s Dakota Johnson who will be The Franchise. The film will rise or fall based on whether the audience has chemistry with the lip-chewing Ana.

Right now, the franchise is all but a blank slate. This month’s Need for Speed, a film about racing in which Johnson appears opposite Aaron Paul, will offer a taste. But if moviegoers have seen her at all before now, it’s been as Justin Timberlake’s Stanford one-night stand in The Social Network or as Jason Segel’s soon-to-be ex in The Five-Year Engagement. In total, they account for less screen time than a music video.

To say Fifty Shades has been omnipresent in popular culture since its release in 2011 does a disservice to the word omnipresent. It was just over two years ago that an unknown writer named E L James, a British housewife and former television executive previously known for penning Twilight fan fiction under the name Snowqueens Icedragon—yes, really—published the story of a virginal college student, Anastasia Steele, who meets Christian Grey, a young Ayn Randian master of the universe with a predilection for helicopters, Audis, and sexual equipment borrowed from some combination of a Soviet torture chamber and Caligula’s basement. They fall into a sort of love that includes whips, chains, and nondisclosure agreements.