Diane Keaton, Emma Stone, Julia Roberts party at Hammer gala

It was a celebration of individuality Saturday night at the Hammer Museum’s Gala in the Garden, a fundraiser for the museum that has become so successful in its 13 years that it has nearly outgrown its garden setting.

Neither heat wave nor Obamajam could spoil the party sponsored by Bottega Veneta, which started with cocktails and gallery hopping, moved to the courtyard for dinner, and capped off with a feel-good performance of Marvin Gaye’s “What’s Going On” by Aloe Blacc. The event raised $2.5 million for the museum.

“L.A. is now the cultural capital of the world,” enthused L.A. Mayor Eric Garcetti, kicking off the evening by speaking to the crowd, including the evening’s honorees, actress Diane Keaton and L.A. artist Paul McCarthy, as well as gala co-chairs Julia Roberts and Danny Moder, Sam and Aaron Taylor-Johnson and Bottega Veneta Creative Director Tomas Maier.

“All of you gentlemen should take your jackets off,” Hammer Museum Director Ann Philbin announced as people fanned themselves at their tables. “I would do the same with my leather dress if I could.”

Of course, when you’re artist Mark Bradford, you can wear a T-shirt and jeans to a gala and look great doing it. Always seemingly sweat-resistant, Keaton wore her signature black fedora with a gold-flecked Comme des Garcons sack dress and black turtleneck sweater. “I thought I could highlight my legs,” she said. And she did, perfecting the ankle bootie-as-evening-shoe trend, with a pair of chunky-heeled Chloe boots.

Meanwhile, television writer and arts patron Maria Bell paid homage to Keaton by working an “Annie Hall” look in a long Chloe skirt, silk tie blouse and vest.

Many other guests wore Bottega Veneta, and it’s a testament to Maier that they all managed to look like individuals, rather than clones in a brand army.

“You see people dressed from four or five different collections,” said Maier. “It’s nice, because they are investment pieces.”

Filmmaker and author Liz Goldwyn, whose sexy homage to 1890s Los Angeles, “Sporting Guide” (Regan Arts) is out this week, wore a strapless denim Bottega gown with floral embroidery and a saucy side slit. Marissa Tomei chose Bottega’s black-and-white checked trousers and a pale pink silk tie blouse.

Salma Hayek Pinault’s Bottega gown, in dark green with an embroidered bodice, had a more exotic vibe, while Emma Stone’s gilded black lace Bottega sheath was short and sweet.

McCarthy, whose artwork challenges consumer society and mass media, with a particular focus on Walt Disney, held the audience captive for more than 10 minutes with his acceptance speech, read from his phone, a kind of free association of words mentioning museum boards, “Helter Skelter,” Reaganomics, Andy Warhol and artists Chris Burden and Mike Kelley.

The tribute to Keaton was lighter; she was praised for her film work, as well as her dedication to historic preservation. Martin described Keaton as “an exciting person who is very spontaneous.” Stone described her as someone who would rather “see than be seen,” adding, “Diane is my hero because she makes me want to be more like me.”

Then Keaton took the stage and put the focus back on the museum: “We’re here to honor art and everything it gives us,” she said. “We’re just one big Hammer family.”

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