"It hasn't been a great week for dogs so with a heavy heart I must tell you, Sweet Chester (aka Cheddar cheese) has passed away," Cuoco shared on Friday. "We rescue these angels blindly and have no idea what problems they may have. I'm still in shock but I just keep feeling blessed to have him in my life even for a small amount of time."
"He was such a joy- hilarious ears and followed me everywhere I went," she continued. "He loved people so so much- loved being held and cuddled. Slept right on my pillow every night. I can sleep knowing that he felt extreme love towards the end of his life."
Chester was one of four dogs to share the actress' home -- along with Norman, Shirley and Ruby, plus a horse named Zaza. Cuoco had only recently adopted Chester, introducing her new pup in October 2015.
In November, Cuoco hosted Fox's All-Star Dog Rescue Celebration, encouraging people to adopt shelter dogs.
"Norman's my main man," she told ET of her most frequently Instagrammed dog. "Norman's always been my main man, and he will always continue to be. I mean, I think I'm actually going to put a tattoo of him on me. That's how much I love him."
"He's everything," she continued. "We've been through a lot together and, yeah, he's very near and dear to my heart."
But Cuoco wasn't the only one gushing over adorable dogs at the event -- executive producer Hilary Swank totally lost it while cuddling with a tiny puppy during an interview with ET! See the moment below.