Charlize Theron ''Flux''-es her Hollywood muscle

At this year’s Oscars, Charlize Theron was sitting awfully pretty for playing ugly. Accepting the Best Actress award for her performance as serial killer Aileen Wuornos in ”Monster” — a role for which she’d gained 30 pounds and made herself stupendously hideous to behold — Theron radiated a distinct golden glow, to the point where some viewers might have felt compelled to adjust their TV sets. Alas, in Hollywood, you’re given just one evening, really, to bask in Oscar glory — and you’d better enjoy it, because by the time the champagne’s worn off, the question’s already sinking in like a hangover: Where do you go from here?

Theron’s answer to this question, which has plagued so many Oscars winners, has become clearer over the last few months. In April, the actress, 28, signed on to produce and star in Universal’s ”Jinx,” based on an acclaimed graphic novel about a female bounty hunter. In July, she’ll start production on another animation-based feature, Paramount’s sci-fi epic ”Aeon Flux,” in which she plays an assassin in a skintight suit. Both movies look like a bid for franchise stardom — and she’s reportedly earning a career-topping $10 million for Flux. But neither is a brand name on the level of, say, Angelina Jolie’s ”Tomb Raider” or Halle Berry’s ”Catwoman.” ”Flux” is being directed by Karyn Kusama, whose only previous credit is the low-budget drama ”Girlfight.” And ”Jinx” isn’t your typical Jerry Bruckheimer-style blockbuster slam dunk. ”It’s a character-driven piece,” says David Engel, another producer on the film. ”It’s not a big summer movie.”

Theron is maintaining her art-house chops as well. In September, she’ll star in the 1930s period drama ”Head in the Clouds,” which centers on a love triangle between Theron, her real-life beau, Stuart Townsend, and Penelope Cruz. In December, she’ll appear as Swedish actress Britt Ekland in an HBO biopic about the late Peter Sellers.

The what-next question is especially pressing for an actress like Theron, who, while hardly unknown before her ”Monster” triumph — having starred, most notably, in 1997’s ”The Devil’s Advocate,” 1999’s ”The Cider House Rules,” and last year’s ”The Italian Job” — is still not firmly perched on the A list. Plenty of Oscar winners, from Marisa Tomei to Mira Sorvino to Helen Hunt, have seen their magical coaches turn quickly back into pumpkins. ”An Oscar in itself doesn’t give you longevity,” says a representative for one past Best Actress winner. ”Charlize still has to prove she can carry a movie — not as an actress but as a commodity, a celebrity.”

There’s no single formula for how to follow up an Oscar win. Some actors opt to work only on prestigious material to keep their Academy-burnished auras shining — the approach, more or less, of Nicole Kidman, who went from her 2003 Oscar for ”The Hours” into a string of eminently respectable projects, culminating in ”Cold Mountain.” Others try to goose up their marquee value with a mass-appeal romantic comedy or action movie, as Berry did in going from the grit of ”Monster’s Ball” to the gloss of the Bond film ”Die Another Day.”