Kaley Cuoco and Johnny Galecki found love while playing on-screen couple Penny and Leonard on "The Big Bang Theory." Though their real-life romance was short-lived, it laid the foundation for their enduring friendship.

Cuoco and Galecki dated for two years, then broke up in 2009, just as their characters were getting together. However, they remained close and continued working together until the show ended in 2019 after 12 seasons."The love was so real between Penny and Leonard in the beginning, " Cuoco told Dax Shepard's podcast in 2022. "Johnny and I fell madly in love the first couple of episodes."

The pair bonded over "the workload and the hours and the comedy," Cuoco said. Though they eventually transitioned into friends, their early connection benefited their onscreen partnership."I think it was good for the show because that was authentic, " Cuoco said. "You could feel it."Even after they split, Cuoco and Galecki's affection for each other translated to their characters. "When we did break up, it was so weird and so sad," Cuoco recalled. "But it was weird how it never changed anything."

Their ability to remain platonic scene partners led to a fulfilling creative collaboration that lasted over a decade. "We cared enough about each other that we didn't want to hurt the other person and go through [an] uncomfortable moment," Cuoco noted. "We powered through and made an amazing relationship that now is a great friendship."

Though Penny and Leonard's happily ever after brought "The Big Bang Theory" to an end, Cuoco and Galecki's connection lives on. "Who gets to do that with an ex?" Cuoco marveled. "No one. No one does that. We celebrated 12 years of a job well done." The actress considers herself "so lucky" to have that relationship in her life, both personally and professionally.

Galecki was similarly appreciative of his experience working with Cuoco. "We were all very close and remain very close," he told Us Weekly in 2019. "So we were certainly each other's support systems through those 12 years." Their real-life bond, like Penny and Leonard's, stood the test of time and change, allowing them to create a memorable on-screen love story that was grounded in reality. Years later, Cuoco and Galecki continue to look back on their time as TV's favorite couple—and real-life sweethearts—with gratitude and affection.