In the photo, Cuoco and Karl Cook are donning a tandem Christmas sweater that is joined in the middle. Cuoco's side reads, "I've been nice," and Cook's side reads, "I've been naughty."
"When you are my really reeealllyyyy getting into the holiday spirit!! falalalala lalalala!! [Karl Cook,] my other half," Cuoco wrote in a caption of the photo.
Cucoco is no stranger to silly gags or pranks, as earlier this year at San Diego Comic Con, she revealed that the cast of The Big Bang Theory once pulled a prank that did not go as planned.
During the audience Q&A session, one fan asked, "Are there pranks on set? Or surprises you plan for each other?"
Cuoco then recounted the prank that she and Johnny Galecki attempted to pull but went terribly wrong.
"Our gag reels are very funny, the Valentines Day Episode for Season 6 and the scene was us fighting (Johnny) and so we thought it would be funny if we took it way too far and Johnny would punch me for the gag reel. And set it all up and called makeup to get extensions so that it would freak everyone out," she said
"And so we did it, but I fell over, and the chair flipped over and hit me in the head. But we didn't know it did anything, and so Johnny kept going with fake punching me," Cuoco added.
"Then when we came up from it my head was busted open and my real blood was everywhere and everyone was panicked. So then I had to go get stitches and we had to reblock the shot," she recalled, then explained, "So if you watch the show, I am faced in another direction because I had stitches."