"It was a zoo in here," Brad Fuller, the restaurant's general manager, tells PEOPLE about the celeb-packed eatery. (In addition to Aniston, Demi Moore, Ashton Kutcher, Cameron Diaz, beau Alex Rodriguez, Mario Lopez and more were dining simultaneously.) "People were wanting to get a look once word got out that they were all here."
Aniston was there with her Just Go with It costar Adam Sandler, though they sat at separate tables, and various employees of Sony Pictures.
"She seemed super nice and seemed to be enjoying herself," Fuller says, adding that Aniston had her own private security team dining with her. "They were mixing it up and having a lot of fun."
Fuller says the actress was "smiley, happy, upbeat" and "socializing with the table." Aniston was also dressed up and ready to attend other parties in town, Fuller says.
As for the other celebrity diners, Diaz and Rodriguez were in the front of the restaurant, eating with a friend from Dallas. And when it was time to leave, they were escorted through the kitchen to their car.
"She was super nice and thanked me on the way out," Fuller says of Diaz. "She and Alex both looked great; they were at a table right up front, but most everyone left them alone."
But not everyone got lucky enough to get a seat at Al Biernat's.
The night was so crazy that Fuller says he had to turn down Diddy's request for a party of 20, along with a reservation request from the band Nickelback.
"I hate to say 'no,' " Fuller says. "But there was nowhere to put them."