Eva Chow and Leonardo DiCaprio

Eva Chow and Leonardo DiCaprio are co-chairing the Art and Film Gala for the Los Angeles County Museum of Art. (John Shearer / Getty Images for LACMA / August 26, 2012)

Celebrity presence has always been an essential part of the game at Los Angeles charity events, but this fall organizers may have outdone themselves. Consider:

George Clooney will be honored at the Carousel of Hope Ball.

Leonardo DiCaprio is co-chairing the Art and Film Gala for the Los Angeles County Museum of Art, where Steven Spielberg is slated to deliver a tribute to the late filmmaker Stanley Kubrick.

MSNBC's Rachel Maddow and comedian-actor-musician Steve Martin will speak on behalf of artists Barbara Kruger and Cindy Sherman, respectively, at the Hammer Museum's Gala in the Garden.

And if that's not enough star power, pop supernova Katy Perry has signed on to perform.

In the high-stakes game of charity fundraisers, where one night's take can exceed $1 million and on occasion top $3 million, gala organizers are clearly making it a priority to line up A-listers to honor, present, emcee and entertain.

This makes sense, especially in Los Angeles. After all, Hollywood's royalty is part of the greater community too. But does such luminosity make a difference to the bottom line? Most gala organizers say they already have a base of support, but, yes, the celebrity factor is meaningful. Especially now, given the ever-present attention to celebrities on the Internet and the popularity of social media that allow celebrities to tweet their every move and passion to loyal followers.

David Morehouse, assistant director of donor relations at the Hammer Museum, whose Gala in the Garden is scheduled Oct. 6, says most of the guests buy a table because they love the Hammer. But he agreed celebs are a draw.

"Someone might decide to come because they love Cindy Sherman or Barbara Kruger, or because Steve Martin is funny," he said. "Maybe they're fans of Rachel Maddow and they'll buy a $25,000 table." And lest anyone doubt Perry's appeal, the recording superstar has more than 25 million Twitter followers (@katyperry).

For the Los Angeles Philharmonic, there's no need to stray far for a big name — Music Director Gustavo Dudamel is a rock star of the music world. "Gustavo is world-renowned," said Joan Hotchkis, gala co-chair along with Carolyn Powers.

At the "The Philharmonic Dances" on Sept. 27, the maestro will conduct a program of ballet, contemporary and Broadway-style dancing, before joining guests for dinner and dancing.

Likewise, the L.A. Opera has its own world-renowned star, Plácido Domingo, as general director. At Ignite! A Gala Celebration on Sept. 15, guests will dine and hear Domingo sing his 140th role in "The Two Foscari" before he, conductor James Conlon and the cast head over to the "Aria" after-party, chaired by Stana Katic of TV's "Castle."

Katic's involvement is no one-time fluke. She comes often to the L.A. Opera, and gala chair Jill Baldauf said she "couldn't be happier" that the actress is taking part in this year's plans.

Baldauf said that when "Shameless" star Emmy Rossum chaired the party last year, the result was an avalanche of attention.

"People could see it was a fun party," she said, adding that ticket sales for this year's gala brought in $1 million so quickly that the committee raised its goal to $1.5 million.

"The whole media scene has changed," said Judy Levy of Levy Pazanti & Associates, which specializes in event coordination and fundraising. "Like everybody else, celebrities are committed and care and want to give back, but now they have more opportunities to let people to hear about it.... There's no down time. You can be tweeting, texting, emailing 24/7."

And Levy believes that's a good thing, saying, "Special events should be 50% money and 50% building awareness."

So what if some guests don't recognize the latest pop stars? Publicist Katy Sweet said the balance is more important. "The charity has to bring in younger people to continue to grow. Maybe some guests don't know a name, but their kids do."

Spielberg famously remarked in 2009 when being honored by the Anti-Defamation League: "What my kids will remember is that I met Adam Lambert tonight."

The whole world knows Clooney, but Carousel of Hope chair Barbara Davis said she got the idea to honor him while watching "The Descendants." She had gone to see the film with a friend, music impresario Clive Davis.