HOLLYWOOD - The stars are not twinkling bright this summer.

Hollywood's movie studios, hopeful that marquee-name actors would push their summer box-office receipts to record levels, are finding that the heavyweights aren't winning over audiences like they used to. With all but a couple of big-budget films already opened, the summer of 2009 is shaping up to be one of the worst on record for Hollywood's A-list talent.

The studios stocked this summer's release schedule with "star vehicles," including Land of the Lost with Will Ferrell, Year One featuring Jack Black, Imagine That with Eddie Murphy, and Denzel Washington and John Travolta in a remake of The Taking of Pelham 123. But rather than igniting ticket sales, the star-studded movies have underperformed dramatically.

The brightest stars of the lucrative popcorn season - which typically accounts for about 40 percent of annual ticket sales - instead have turned out to be mostly movies with no-name actors - or no actors at all.

So far, the summer's most profitable film has been Warner Bros.' surprise hit The Hangover, a $35 million-budget R-rated comedy about a bachelor party in Las Vegas that boasts not a single household-name actor but has reached $183 million in U.S. ticket sales since its June 5 opening and is expected to exceed $200 million.

Other summer hits like J.J. Abrams' Star Trek and Michael Bay's Transformers: Revenge of the Fallen showcase eye-popping visual effects along with up-and-coming talent.

And, the highest-grossing summer movie so far? Walt Disney's Co.'s Up, the Pixar-animated movie starring the voice of ... Ed Asner.

The studios, which for years have banked on richly paid stars to open movies, are witnessing a new reality: Even the most reliable actors can be trumped by what Hollywood executives like to call "high concepts" (a bachelor party gone awry), movies based on brand-name products (Hasbro's Transformers toys), and reinvented franchises (not your father's Star Trek).

"I think we're seeing a transformation in what the value of the star system represents," said Marc Shmuger, chairman of Universal Pictures, which will take a significant loss on Ferrell's Land of the Lost, a film that cost $100 million to make and tens of millions more to market and distribute.

There's also, he said, an "incredible hunger among audiences for something new and different."

Indeed, that was the appeal of the buddy comedy The Hangover.

"Movie stars still hold an incredible value both creatively and financially," Hangover director Todd Phillips said. "But it's getting to be more about the movie and whether it delivers on the promise of its trailers and commercials."

Moreover, with the Internet, word of mouth about movies spreads instantly.

"There used to be a free weekend where marketing departments could open a movie and if it didn't work, word didn't get out until Monday, but that's evaporated with Facebook and Twitter," Phillips said. "The water-cooler effect is much more immediate."

Even before a major movie hits the big screen, Twitter users and bloggers are weighing in - which can help or hinder audience appeal.

"The world has changed, throwing conventional wisdom out the window," former studio marketing executive Peter Sealey said. "The star power opening is fading in importance and the marketing and releasing of movies is going into new territory where the masses are molding the opinion of a movie. People no longer say, 'It's a Tom Cruise movie, let's go see it!' With social networking, you know everything about a movie before it comes out."

Doug Belgrad, production president of Sony Pictures Entertainment, whose studio is behind Year One and Pelham, said stars alone no longer could compete against the draw of franchise movies and sequels like Transformers and Harry Potter that come with a high degree of public awareness.

"Movie stars in the right films provide a certain amount of value from a marketing point of view," he said. "But there is no star power that you can throw at a movie that gives you the kind of brand awareness you get from presold titles."

Even before the summer movie season began in earnest on Memorial Day weekend, there were flashing yellow lights that older audiences were shunning more serious fare despite the stature of the lead actor.

Universal's recent releases, State of Play starring Russell Crowe and Ben Affleck, and Duplicity with Clive Owen and Julia Roberts (who not long ago was Hollywood's most celebrated female star), both bombed, as did Universal-DreamWorks' The Soloist, starring Robert Downey Jr. and Jamie Foxx.

Of course, the right star in the right movie can still lure large audiences, as evidenced by 20th Century Fox's Ben Stiller sequel Night at the Museum: Battle of the Smithsonian and X-Men Origins: Wolverine, in which Hugh Jackman helped attract female moviegoers.

The Proposal, Disney's romantic comedy starring Sandra Bullock and Ryan Reynolds, had a strong opening two weeks ago at more than $33 million and will be profitable since it cost only about $40 million.

"There's something to be said for chemistry between actors, and you don't need to be a star to have chemistry," said Oren Aviv, Disney's president of production, suggesting that is exactly what the casts of The Proposal, Star Trek, and The Hangover all have in common - "combined with an idea that people connect with."