Kaley Cuoco Sings ‘Big Bang Theory’ Theme Song On ‘The Tonight Show’

Kaley Cuoco has been starring in “The Big Bang Theory” for the past 10 seasons, but it was still a treat when she revealed that she knows every lyric to the show’s theme song.

During her appearance on “The Tonight Show,” a fan asked Cuoco if she can sing the theme song. Cuoco replied, “I can try,” but everyone was impressed when she belted out all of the words correctly.

“Our whole universe was in a hot, dense state / Then nearly 14 billion years ago expansion started, wait! / The earth began to cool, the autotrophs began to drool / Neanderthals developed tools / We built a wall / We built the pyramids / Math, science, history, unraveling the mysteries / That all started with the Big Bang! / Hey!” she sang.

Read: Will Sheldon allow Amy to pursue her fellowship at Princeton in “Big Bang Theory”?

According to People, “Big Bang Theory” creators Chuck Lorre and Bill Prady reached out to Ed Robertson of Barenaked Ladies to come up with a catchy theme song that will encapsulate the essence of Big Bang in just 32 seconds.

Cuoco also told “The Tonight Show” host Jimmy Fallon that they recently wrapped up filming for Season 10. “It’s been a wild ride,” she said.

When Fallon noted that 10 seasons means over 200 episodes, Cuoco said that it was about 230 installments for the hit show. “It’s a lot. We’ve had a lot of fun this season. It’s really cute this last season, one of writer’s assistant started asking if she could take behind the scenes photos so she could keep memories of the show. And I was like, ‘That was such a sweet idea.’ And it started at the beginning of the season,” Cuoco said.

The actress went on to say that when she received copies of the photos, she was surprised to see that she’s always looking straight into the camera. More often than not, the photos were taken while the cameras were rolling so Cuoco couldn’t believe the fact that she might not have been focusing on her work. At this point, Fallon brought out three of the photos, and the first one shows the actress smiling while her co-stars are huddled together working.

A second photo shows the staff and crew of “Big Bang Theory” standing in front of Sheldon’s (Jim Parsons) and Leonard’s (Johnny Galecki) white board. Cuoco is once again standing very close to them and smiling towards the camera. The third and most hilarious photo was taken during camera blocking. A “Big Bang Theory” director was giving Cuoco instructions, but the actress was once again not concentrating on her work and was looking at the camera.

Luckily, Cuoco still has plenty of time to redeem herself on set. After all, CBS just renewed “Big Bang Theory” for Seasons 11 and 12. Both seasons will feature a total of 24 episodes, and Cuoco, Parsons, Galecki, Kunal Nayyar and Simon Helberg are all expected to receive $900,000 per episode. Mayim Bialik and Melissa Rauch, on the other hand, will be receiving $500,000 per episode, according to Variety.

“Big Bang Theory” Season 10 airs Thursdays at 8 p.m. EST on CBS.