What is your definition of love?

That’s the question The Big Bang Theory stars are asked to answer in an adorable new featurette that’s included on the hit comedy’s season nine DVD and Blu-ray set, available Tuesday, and ET has the exclusive first look!

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Most of the Big Bang cast members struggle to formulate an answer when asked how their respective characters would define romance, but Kunal Nayyar starts it off on a promising note. “Raj is a romantic at heart,” he said.

“Love being more of a feeling and when science can’t answer what that feeling is, it’s love,” Jim Parsons offered, prompting co-star Mayim Bialik to chime in: “It’s still kind of romantic.”

But Kaley Cuoco went the personal route, admitting that she has no definition for love.

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“I don’t even know how Kaley would define love! I don’t know!” the 30-year-old said actress through nervous laughter.

In June, Cuoco shared a cute snap on Instagram of herself and her equestrian boyfriend, Karl Cook, giving her four-legged friend a smooch. “Not sure who I miss more,” she sweetly captioned the pic.

The Big Bang star couldn’t seem happier with Cook, 25, who bonded over their shared love over all things equine.

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“He’s special,” she gushed to ET. “I think that the horse connection is special. Yeah, he’s special.”

The Big Bang Theory premieres Monday, Sept. 19 at 8 p.m. ET/PT on CBS.

To find out more about Cuoco’s romance with Cook, watch the video below.