Actress Kristen Bell, 24, went from Broadway crooner and occasional TV guest star (Deadwood) to headliner of UPN's popular high-school detective series Veronica Mars (Tuesdays at 9 pm/ET). The dishy Detroit native now carries the weight of an entire show on her petite shoulders with aplomb.

"It's been a very, very good thing," the perky blond smiles, "but it's tough to accomplish because you're only one person, and it seems like I need to be in so many places at once. So it's definitely a lot more work than I think I had anticipated, but the payoff is extraordinary. The publicity has really created a much wider fan base, and I'm just very, very grateful for it."

You're welcome, Kristen. Pressed for some scoop, the small-screen sleuth insists her bosses haven't clued her in on the identity of Lilly Kane's murderer. This Mars case rivals Desperate Housewives' unsolved mysteries in its wacky twists and turns. "They don't tell us anything," she says. "We've been taking bets on set.

"I'm pretty sure I figured it out," she adds confidently, "to the point where I haven't told any of the other cast members — nor have I told anyone [else], because I'm that sure. I still could be wrong, but I've used a little bit of Veronica's skills to figure it out [with] what I know in advance about the show, what I know is airing, where I know [the writers are] going with certain people. So I think I know who it is, but no one knows for sure." Our money's on Jake Kane.