Kaley Cuoco and Johnny Galecki discuss their hidden romance.

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Kaley Cuoco and Johnny Galecki, who used to be her boyfriend, recently talked about why they kept their relationship quiet while filming The Big Band Theory.

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From 2007 until its end in 2019, the popular sitcom ran for a total of 12 seasons. Kaley, who is 36, and Johnny, who is 47, started dating in 2007 and broke up in 2009.

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The actors told Vanity Fair that they didn't tell fans about their relationship because they didn't want to "ruin" how fans saw Leonard and Penny.

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Kaley told the magazine, "When Johnny and I were dating, he was worried about ruining the fans' view of Leonard and Penny,

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even though they weren't dating yet on the show." She also said that at the start of their relationship, they each had different ideas about what was going on.

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I was like, "What?!" because he was so smart. What on earth is the point?!"They'll be fine!" she told them.

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The actress from Flight Attendant told Vanity Fair, "In retrospect, I kind of get it."

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He was very worried about what the fans would think, because we wanted them to want Leonard and Penny together so much that if they saw us together in real life,

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it would ruin the fantasy, Kaley said. Johnny also spoke up and asked, "What would happen if we broke up? How would that change how they see the characters?

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He also said, "It was hard for me at the time, so we didn't talk about it." And Kaley was really good about sticking to the rules I set.'

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The actor from Roseanne talked about some of the problems.

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