On The Big Bang Theory, Johnny and Kaley played neighbours-turned-lovers from 2007 and 2017, but you may not realise that the actors also dated in secret from for two years. They got together soon after meeting on the show but decided to end their own romance in 2009.
Kaley first opened up about their relationship during a September 2010 interview with CBS Watch!, and she had nothing but good things to say about it. "It was such a huge part of my life and no one knew about it," she said. "This is the first time I've ever talked about it, ever. It was a wonderful relationship, but we never spoke a word about it and never went anywhere together." Later, she added, "We knew we weren't destined to be together. We accepted it and said, 'Look, if we ever break up, we will be professional.' I'm so lucky it was a mutual ending and that we don't hate each other."
Johnny expressed a similar sentiment during his own interview with CBS Watch! in December 2013, saying that he and Kaley remained close. "We're dear friends, still. Kaley's not just an ex — she's a part of my life," he said. "I just don't like to speak about it. And not because I'm trying to be enigmatic; I just worry that it will conflict with people's acceptance of Leonard and Penny. I get the curiosity, but I don't want to distract from the story."