Big Bang Theory
Johnny Galecki and Kaley Cuoco as Leonard and Penny in The Big Bang Theory CBS

Johnny Galecki wished his The Big Bang Theory co-star and on-screen wife Kaley Cuoco on her 32nd birthday on Instagram and it is "hilarious". In the first post he called Cuoco his "fake wife," and for the second post, he had help from Cuoco's fiance Karl Cook.

Galecki shared a photo of himself with Cuoco and wrote, "HAPPY BIRTHDAY to the best fake wife anyone could ever ask for. And a pretty great friend to boot. Much ❤️. 11 years together and you've rarely smelled better."

For a second snap, he cut out most of Cuoco and kept her fiance Karl Cook and himself in the frame. While Galecki and Cook are smiling, only a small portion of the Penny actor's face is seen peeping out, as the caption read, "Another HAPPY BIRTHDAY to the stunningly beautiful Kaley Cuoco!!!"

The Big Bang Theory fans are flipping out over the hilarious photo shared by Galecki. One user wrote, "Hahaha haha!!! this is great," another commented saying, "That's hilarious."

"Lol so funny she is the bday girl and only her eye comes out in the picture," pointed out one Big Bang Theory fan. Before meeting her equestrian soulmate, Kaley and Johnny dated for two years while working on the CBS show and broke up in 2009.

Complimenting Kaley and Johnny's friendship, a user wrote, "Best couple ever.... I really appreciate people who are able to continue as friends," as another gushed, "You guys are friendship goals! I love you."

The CBS actress' 32nd-birthday was made special when Cook popped the question during the birthday dinner.

Cook shared a video of the emotional proposal on Instagram in which Cuoco has tears streaming down her face as she says, "We're engaged!" Karl responds saying, "You still haven't said yes yet," to which she yells out, "Yes! I say yes! I say yes!"

Later, he shared a photo of him embracing the moment and his fiancee, and wrote a small tribute dedicated to his to be wife, "In life, there is nothing like dancing right after getting engaged. The purity and grace of the moment are inexplicable, it is truly as though life were a balloon bouncing on the smoothest zephyr.

"Honey; all I want is to be a balloon bouncing, bobbing, and flowing through life together. You are my everything," read the caption.