Demi Moore bizarrely picked up a stray kitty that managed to crash an exclusive Chanel party Wednesday night at Miami’s Art Basel and took the puss to dinner as her date.

Spies say the star picked up the stray when it wandered by the Soho Beach House’s pool and brought it to dinner, where, “The kitten sat on Demi’s lap throughout the meal . . . She was cuddling and petting it.”

But that was the only heavy petting she was doing in public. Moore, 50, showed up without boy toy Vito Schnabel, 26, to the Chanel bash where guests included Stacy Keibler, Aby Rosen, Klaus Biesenbach, Richard Prince, Jeff Koons and Vito’s dad, Julian.

PHOTOS: DEMI MOORE

After dinner, Moore ditched the feline and headed to a packed after-party for art-collecting site Art.sy, where guests included Will Ferrell, Karlie Kloss, Adriana Lima, Jeremy Piven and Pharell Williams, along with artists Damien Hirst and Urs Fischer. Wearing a very short pantsuit and black-rimmed glasses, Moore squeezed onto a sofa with Lenny Kravitz swilling can after can of Red Bull.

As Moore engaged in caffeine-fueled, suggestive dancing with friends, dapper art dealer Vito hovered nearby, exchanging glances with her. Yesterday he denied to a photographer in Miami Beach that he’s seeing Moore.

“Vito and Demi didn’t want to be pictured together,” a spy explained. “They want to keep their relationship as private as possible, and he is determined to be taken seriously in the art world rather than be known as a celebrity.”

At 1 a.m., Moore and Keibler headed to Le Baron’s pop-up club at karaoke bar Jelsomino. “They sat with five guy friends and were dancing together,” a spy says. “They were offered tequila shots, but Demi declined, saying ‘no shots,’ while Stacy and her friends happily knocked them back. They left at around 3 a.m., and amazingly, said they wanted to go on to another club.”

Demi’s said to be staying at Alex Rodriguez’s Miami Beach mansion, along with Keibler, a close friend of A-Rod’s gal pal Torrie Wilson.