'Big Bang Theory' Star Johnny Galecki Congratulates Kaley Cuoco on Marriage to Karl Cook

The Big Bang Theory star Johnny Galecki congratulated his on-screen wife on her big day on Sunday, as co-star Kaley Cuoco officially tied the knot with Karl Cook on Saturday night.

"Deepest congrats to the newlyweds," Galecki wrote, posting a photo from the wedding standing in between the new couple. "Love you both so much [Kaley Cuoco] & [Karl Cook] So moved by tonight."

Fans of the CBS comedy thoroughly enjoyed the photo, pointing out the running joke where both stars attempt to crop each other out of photos.

"How beautiful that they remained such good friends," a fan commented.

"Was it weird going to your wife's wedding?" another joked.

"They really do have a cute relationship. Love them both," wrote another.

Cuoco broke the news on Saturday night with a photo of her in a long white wedding dress and Cook in a black tuxedo as they shared a kiss inside a heavily-decorated horse stable.

"Legally KCSQUARED 6-30-18," Cuoco wrote, referencing the couple's nickname of having identical initials.

She then shared a photo from the reception, where she had changed into a white jumpsuit and he had put on a more casual suit.

"Ok let's party!!" she wrote.

On Sunday, she returned to Instagram with a new photo of the couple in matching denim jackets with the phrase "Together Forever" and "KC Squared" embroidered on the back.

Cuoco and Galecki previously dated for two years while shooting The Big Bang Theory, and remained friends even after breaking up in 2009.

Cuoco was previously engaged to Josh Resnik in 2011, but the engagement was called off in March 2012. She then married tennis player Ryan Sweeting in September 2013, which lasted for roughly two years before separating in September 2015.

She and Cook, an equestrian, first began seeing each other in later 2016.

The wedding itself was officiated by Cuoco's sister, Briana.

"Oh my gosh. I love you both so much," she said to close the ceremony in a video posted to Instagram. "Everyone is here and travelled across the country and across the state because we love you so much. It will be our privileges to watch as you go on this amazing journey together. So by the power invested in me by the state of California and a very questionable website where I got ordained, I now pronounce you husband and wife."

On the comedy series, Cuoco and Galecki's characters began dating in the first season. After a breakup and reunion, the two continued dating and got married in the first episode of Season 9 in 2015.