Kaley Cuoco
Kaley CuocoInstagram/NormanCook

The cast of CBS' primetime show "The Big Bang Theory" was out in full force at an Alzheimer's charity benefit at the Beverly Hilton on Wednesday, and actress Kaley Cuoco stole the show with a backless black dress.

The 29-year-old flashed some skin at the gala held for the Alzheimer's Association with her plunging back number, which she accessorised with a long chain that she wore backwards.
Cuoco kept her makeup to the bare minimum and styled her bob into a messy do.

Cuoco, who is married to tennis player Ryan Sweeting, was accompanied by her "The Big Bang Theory" castmates, including Kunal Nayyar, Simon Helberg, Jim Parsons, Johnny Galecki and Melissa Rauch.

Proving that she's still in friendly terms with her ex, Galecki, Cuoco was photographed hugging her "Big Bang Theory" love interest as they posed for pictures.

Cuoco and Galecki, who have been starring together on the CBS hit show since 2007, dated for two years before parting ways. The duo kept their romance a secret for a long time, and Cuoco opened about it only in 2010, saying they were protective of their relationship.

"We dated for almost two years. It was such a huge part of my life and no one knew about it," Cuoco revealed to CBS Watch! magazine, according to Us Weekly. "This is the first time I've ever talked about it, ever. It was a wonderful relationship, but we never spoke a word about it and never went anywhere together."

"[We were] so protective of ourselves and the show, and we didn't want anything to ruin that," she said.

When asked about his reason for keeping their romance a secret, Galecki said he did not want their off-screen romance conflicting with their on-screen relationship.

"We're dear friends, still. Kaley's not just an ex, she's a part of my life," Galecki told CBS Watch! magazine. "I just don't like to speak about it. And not because I'm trying to be enigmatic; I just worry that it will conflict with people's acceptance of Leonard and Penny. I get the curiosity, but I don't want to distract from the story."