The Big Bang Theory stars Kaley Cuoco and Johnny Galecki have opened up about their secret romance.

The pair, who played Penny and Leonard Hofstadter on the long-running show, dated in real life for two years.

The Flight Attendant star Kaley admitted she had a crush on her co-star from “very early on”.

“I was so not even hiding it. He has such swagger,” she told upcoming book The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series.

“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’.”

Galecki added: “I have a healthy ego, but you really have to kind of club me over the head to let me know you’re flirting with me.

“I had zero idea of any sort of crush before Kaley and I began dating.”

The pair decided to keep their romance a secret, with Galecki explaining: “It certainly wasn’t because I was embarrassed of her or our relationship, but I wanted to be protective of the audience’s acceptance of Penny and Leonard, and without distraction from the tabloids.

“I’m private in general, but it made me especially uneasy because we were working together, and the show was kind of snowballing at the time as far as viewership.

“And at a certain point it felt like we were living this lie because we were going to award shows and functions and pretending like we’re not a couple, when in fact we were a very loving couple.”

Despite their split in 2010, they continued to be friends and remain close.

Cuoco said: “I think a lot of what made Leonard and Penny work so well was my relationship with Johnny off camera, which turned into such sarcastic banter that bled into Penny and Leonard.

“Johnny and I’s relationship, in a way, was mimicking Penny and Leonard. They were always giving each other shit, and Johnny and I have a similar relationship – which you do after years of being together.

“We’ve always had each other’s backs, and you can’t lose that. And I do think it happened on-screen. It made our relationship funny and endearing.”


By Ivaylo Angelov

Ivaylo Angelov born in Bulgaria, Varna graduated School Geo Milev is Tvserieswelove's Soaps Editor and oversees all of the section's news, features, spoilers and interviews.