"The Big Bang Theory" cast organized a flash mob in the middle of taping during Thursday night's episode, surprising the studio audience.

"The Big Bang Theory flash mob" video went viral on YouTube with more than 2.7 million views as of Friday evening, just a day after CBS uploaded it.

In the video, the show's cast members Jim Parsons (Sheldon), Johnny Galecki (Leonard),  Kunal Nayyar (Raj), Simon Helberg (Howard), Mayim Bialik (Amy), Melissa Rauch (Bernadette) and Kaley Cuoco (Penny), are seen sitting on a couch when Carly Rae Jepsen's "Call me Maybe" starts playing in the background and they interrupt the scene with a choreographed dance with other cast members and crew.

Only Galecki and Parsons did not dance.

But that wasn't the end of the fun. When the performance concluded, Parsons went back into character and told the crowd "Bazinga!", a term used by his character Sheldon as a followup to pranks or jokes.

Apparently it was Kaley Cuoco the one who organized the flash mob. 

"Ok it's here! The moment I've been waiting for! I finally get to share the surprise!! the BIG BANG THEORY FLASH MON!" she wrote on Twitter Thursday afternoon with a link to the video.

The CBS hit sitcom scored its highest ratings ever Thursday with 17.4 million viewers, according to Nielsen ratings.

The figures are stunning when compared to other TV shows that aired at the same time. Fox's "The X Factor" raked in 7.3 million viewers followed by "Last Resort" with 5.8 million viewers.

Watch The Big Bang Theory Flash Mob Below:

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