Cuoco was put on the spot when an audience member asked if she knew the lyrics, and Fallon urged her to perform them. "I can try," she said, proceeding to tackle the dense tune with zest.
The actress performed the tune for Jimmy and his audience, dazzling as she sang the catchy tune.
The Big Bang Theory creators Chuck Lorre and Bill Prady asked Ed Robertson of Barenaked Ladies to come up with a song that would serve as a "sort of history of everything…in about 32 seconds." The result was this catchy, but wordy theme.
Cuoco and the rest of the cast will now have plenty more opportunities to sing it, as CBS renewed The Big Bang Theory for another two seasons.
Meanwhile, Kaley talked about her time with Karl Cook and revealed that she recently felt like a contestant on The Bachelor.
The actress shared that she was on vacation with Cook's family in New Zealand, where they participated in a lot of outdoor activities. She shared that things got terrifying when they actually hiked up a mountain to get to a zip line.
"But here's the problem. I'm with his family! I felt like I was on The Bachelor! I had to be like, 'Are you ready to take this [step]? Can you jump off with him? This is the next step in your relationship,'" the actress joked. "I'm like, 'Am I gonna get the rose out of this?'"
Although the experience was terrifying, Kaley revealed she had an amazing time with Cook and his family in New Zealand.
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