Kaley Cuoco and Johnny Galecki are some of the friendliest exes in Hollywood.
The two first met on the set of The Big Bang Theory, where they developed a romance offscreen and dated for almost two years.
Though they eventually broke up in real life, their characters continued to date on the series, eventually tying the knot during the show's season 9 premiere and again in the season 10 premiere.
Despite breaking up and going on to date other people, the former costars have maintained a super close friendship over the years.
"I adore the friends that we are," Galecki said in an excerpt from The Big Bang Theory: The Definitive, Inside Story shared with Vanity Fair. "I think I might value my relationship with her more than any other previous relationship or relationship afterwards. We just have such a bond that I appreciate so much. And I think that's part of our great friendship."
From the early beginnings of their love story to their close friendship now, take a look back at their relationship timeline.
2007: Kaley Cuoco and Johnny Galecki meet on the set of The Big Bang Theory
Cuoco and Galecki first met each other on the set of The Big Bang Theory, in which they played Penny and Leonard respectively. Despite being in relationships with other people at the time, Cuoco revealed she "had a very big crush on Johnny early on."
"I was so not even hiding it," she said in an exclusive excerpt from The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series shared with Vanity Fair. "He has such swagger. We were both dating people at the time, but I only had eyes for Johnny. Then, when I found out he had eyes for me too, I was like, Uh‑oh, this is going to be trouble."
2008: Kaley Cuoco and Johnny Galecki start dating
After meeting on set, the couple developed a romance offscreen sometime in 2008. In The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series, they noted that they really came to terms with their feelings for each other while filming the episode "The Nerdvana Annihilation" from season 1, in which Leonard imagines a superheroic rescue of Penny in an elevator shaft.
"I think we fell a little in love in that elevator shaft," Cuoco said of the scene, with Galecki adding, "We felt something, yeah. I think that was a massive turning point [in our relationship]. At that point, both she and I knew that something mutual was felt, and that it was going to be more of a distraction from the work to try and continue to ignore it than to actually recognize it and surrender to it."
After Cuoco split from her boyfriend at the time, the two began dating, though they kept their relationship under wraps for a long time.
"He was very protective of what the fans would think, because we wanted them to want Leonard and Penny together so badly, that if they saw us together in real life, it could ruin the fantasy," Cuoco said of Galecki's decision to keep their relationship out of the public eye.
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2009: Kaley Cuoco and Johnny Galecki break up
After dating for almost two years, the couple quietly split before the holidays in 2009. In The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series, they explained that their breakup was a result of them wanting different things.
"It was a lot of fun to teach one another different things, but then when I came to wanting different things, that made things more complicated," Galecki explained. "We just had very different interests in what I think we wanted from our experience of life."
Cuoco added that their relationship just ran its course, saying "Johnny and I also ran out of things to talk about, because we'd be at work all day, and then we'd go back to one of our places together, and say, 'So how was your day? Simon was funny today, right?' And we'd laugh because we had no mystery. But we were together for a long time. We really adored each other, and we were lucky because as our breakup was happening, there was no foul play, there was nothing bad about our relationship ... it just ended."
Though she admitted that "there was some hurt there for a bit" it didn't take them long "to go back to what [they] were before [they] were dating, and be friends."
Jan. 6, 2010: Kaley Cuoco and Johnny Galecki attend the People's Choice Awards
In early 2010, the two attended the People's Choice Awards alongside their Big Bang Theory castmates as the show took home favorite TV comedy. The duo also posed for photos together backstage.
September 2010: Kaley Cuoco opens up about her relationship with Johnny Galecki
It wasn't until almost a year after their breakup that Cuoco publicly opened up about her relationship with Galecki. In an interview with CBS Watch! Magazine in 2010, the actress talked about keeping that part of her life under wraps for such a long time.
"It was such a huge part of my life and no one knew about it," she said. "It was a wonderful relationship, but we never spoke a word about it and never went anywhere together."
"Everyone was always asking, and we deny-deny-denied," she continued. "And I'm like, 'Why am I denying this person that I love?' "
She added that the secrecy of their relationship contributed to their eventual breakup. "That's not the kind of relationship I want — I don't want to be hiding. We couldn't do anything. It wasn't as fun as we wanted it to be."
Though she added that they are still on good terms, saying, "I'm so lucky it was a mutual ending and that we don't hate each other. We've seen that happen on other shows."
November 2013: Johnny Galecki says he's still good friends with Kaley Cuoco
Kevin Mazur/Getty Images for People Magazine
In a separate interview with CBS Watch! Magazine, Galecki discussed his relationship with Cuoco, setting the record straight on where they stood following their split.
"We're dear friends still," he said. "Kaley's not just an ex, she's a part of my life."
Dec. 31, 2013: Johnny Galecki supports Kaley Cuoco at her wedding to Ryan Sweeting
In December 2013, Cuoco tied the knot with Ryan Sweeting and Galecki was front row to support her.
"It took a minute, a bit of awkwardness. By the grace of God, we became best buddies and moved on in such an elegant way," Cuoco said of her ex in an interview with Cosmopolitan published in April 2014. Calling Galecki one of her "closest friends," she added that the actor "was in the front row at [her] wedding, with a huge smile on his face."
Sept. 20, 2015: Kaley Cuoco reveals that Johnny Galecki loves Ryan Sweeting
During an appearance on Watch What Happens Live, Cuoco spoke about Galecki when a fan asked if it's awkward to film scenes with him on The Big Bang Theory.
"Well, we dated like five years ago, so I think we both moved on," she said. "Johnny is actually one of my best friends. It's a situation that ended well. I understand sometimes it doesn't. It could have gone horrible."
She added that he actually gets along really well with Sweeting, saying, "He's one of my dearest friends and Ryan loves him. Johnny loves [Ryan]. I got lucky."
October 2015: Kaley Cuoco shuts down reconciliation rumors with Johnny Galecki following her divorce from Ryan Sweeting
Following her divorce from Sweeting in September 2015, the actress sparked romance rumors with Galecki when they attended a launch party for the video game Fallout 4 together that October.
However, the actress quickly shut down reconciliation rumors with a since-deleted post on Instagram. "So sorry to disappoint, but no home wreckers or secret flings going on here," Cuoco wrote. "Me and @sanctionedjohnnygalecki are just the best of buds – Leonard and Penny will just have to suffice!!!"
Sept. 21, 2015: Kaley Cuoco and Johnny Galecki's characters get married on The Big Bang Theory
Despite splitting in real life, Cuoco and Galecki's onscreen romance continued to blossom, with their characters getting married in the season 9 premiere and then again in the season 10 premiere.
Cuoco later noted that she felt like the show's creator, Chuck Lorre, purposely added more intimate scenes between their characters just to mess with them.
"When we broke up obviously it was a little sensitive for a minute, but I remember those weeks that Chuck had written these episodes where all of a sudden our characters were like sleeping together every other second," she said during an appearance on Dax Shepard's podcast, Armchair Expert.
"Johnny and I talk about it and I think [Chuck] did that on purpose — just to f--- with us," Cuoco said, laughing. "If I was with him, I would ask him because that came out of nowhere. All of a sudden these characters were all up on each other."
March 2016: Kaley Cuoco addresses ongoing speculation about her relationship with Johnny Galecki
In an interview with Cosmopolitan published in March 2016, Cuoco opened up about the ongoing speculation surrounding her relationship with Galecki, noting that dating rumors were especially sensitive as she was dealing with her divorce from Sweeting.
"Johnny and I are very close now, but the worst part about that is I don't want stories like that, especially during this divorce, to hurt my ex," she said. "We have nods with each other. Johnny and I do this thing like a nod that says, 'I got you. I get it.' "
Jan. 6, 2016: Kaley Cuoco and Johnny Galecki attend the People's Choice Awards together
Cuoco and Galecki sparked dating rumors again when they went as each other's dates at the People's Choice Awards. They also seemed to be especially cuddly, and were seen holding hands.
Despite the friendly night out, the actress once again confirmed they weren't dating. Alongside a photo of her leaning in to kiss Galecki, she wrote, "Thank you for the @peopleschoice award!! Look how happy we are!! @bigbangtheory_cbs season9 #mydate #notdating."
June 30, 2018: Johnny Galecki supports Kaley Cuoco at her wedding to Karl Cook
As Cuoco tied the knot with Karl Cook in 2018, she once again had the support of her ex. Following the wedding, Galecki shared a sweet post on Instagram, writing, "Couldn't be happier for my fake wife @normancook and @mrtankcook whose words brought us all to tears last night. So much love for you both."
He followed up with a playful photo of him, Cuoco and Cook from the reception, which cut off the actress' face. "Deepest congrats to the newlyweds," he wrote. "Love you both so much @normancook & @mrtankcook So moved by tonight. ❤️"
March 2020: Kaley Cuoco says she can't wait to meet Johnny Galecki's baby
A few months later, Cuoco reacted to Galecki becoming a dad, noting that she couldn't wait to meet his newborn. "[Johnny] sends me pictures constantly. He's very proud," she told Us Weekly. "It's really, really sweet. "He's always wanted to have a baby so I think this was really exciting for him."
Nov. 30, 2020: Johnny Galecki wishes Kaley Cuoco a happy birthday
In November 2020, Galecki posted a sweet tribute to Cuoco in honor of her birthday. "The happiest 74th birthday to my fake wife @kaleycuoco," he jokingly wrote alongside a handful of images of them together. "You know how much I adore you and respect you. I'm so proud of all you are doing and so happy with your happiness. But most of all, our friendship and partnership over the years. XO, dear. Congratulations on 82 years of age."
Feb. 14, 2021: Johnny Galecki hilariously reacts to Kaley Cuoco's Valentine's Day tribute to Karl Cook
For Valentine's Day in 2021, Cuoco posted a heartfelt tribute to her then-husband Cook, writing, "Happy 5 years to the weirdest person I know! 🤣♥️ I don't remember a moment before you entered my life.. what a boring life that must have been! I love you @mrtankcook !♥️♥️♥️."
Galecki jokingly took offense to Cuoco's caption, writing in the comments, "Um," playfully referencing their time together.
May 2021: Kaley Cuoco says she talks to Johnny Galecki all the time
Michael Yarish/CBS via Getty
Almost two years after The Big Bang Theory came to a close, Cuoco opened up to E! News about her close bond with the cast. She also touched on her relationship with Galecki, saying, "Johnny and I are very close. We talk multiple times a week."
Dec. 1, 2021: Johnny Galecki wishes Kaley Cuoco a happy birthday
October 2022: Kaley Cuoco and Johnny Galecki open up about their close bond
In an excerpt from The Big Bang Theory: The Definitive, Inside Story shared with Vanity Fair, the former couple opened up about their relationship, sharing never-before-told details about their romance and breakup. They also expressed their continued love for each other after their split.
"I adore the friends that we are," Galecki shared. "I think I might value my relationship with her more than any other previous relationship or relationship afterwards. We just have such a bond that I appreciate so much. And I think that's part of our great friendship."