Sundance, like prom, is an event where young queens are made. Last year, the unofficial crown went to breakout British star Carey Mulligan. This year, the chosen one is Kristen Stewart—hardly an unknown quantity, and an actress who often gives the impression she'd rather be anywhere but in the spotlight.

The 19-year-old Twilight star has had no chance of ignoring it in Park City, of course. Not that its glare has revealed a whole lot: You'd never guess that the quiet, narrow girl going around town in a hoodie and ripped jeans, sporting chopped hair that brings to mind a young Joan Jett, is the star of The Runaways. The movie is the hottest ticket at the festival, although Stewart's other Sundance film, Welcome to the Rileys, in which she plays a Southern prostitute, isn't that far behind.

Jett came to town, too, playing a show with her band the Blackhearts on Saturday night at Harry O's. She got Jared Leto and Catherine Keener to join in on her rebel yell and brought Stewart and her Runaways co-star Dakota Fanning up on stage. No chance of returning to the relative anonymity of the front row after that.

Stewart doesn't chat much, except in handler-approved situations such as the red carpet at the Runaways premiere, where she had this to say about the finer details of playing Jett: "She has a very distinctive growl, and also the way she plays the guitar…" But Stewart's version of the rock legend is younger, more vulnerable than the one most people know. "She wasn't always this intimidating," the actress went on, as Jett did an interview a few feet away. The Runaways depicts a fame-destined girl going through that hardening process—it shows, as Stewart put it, "the building of the armor."

— Darrell Hartman