'Big Bang Theory' flash mob: Cast and crew surprise studio audience with 'Call Me Maybe' dance

The cast of "The Big Bang Theory" broke character big-time during a live taping for Thursday night's (Nov. 15) episode -- with a flash mob!

Just after action was called on a scene for "The 43 Peculiarity," the actors -- including Jim Parsons, Johnny Galecki and Kaley Cuoco -- seemed startled as the opening bars of Carly Rae Jepsen's summer smash, "Call Me Maybe," sounded through the stage. Moments later, the "BBT" crew assembled in front them and launched into a synchronized dance.

Then, with Cuoco -- who orchestrated the surprise and enlisted her sister to choreograph it -- leading the way, the actors got up and joined in as the mob grew. Showrunner Chuck Lorre may not have been in on the gag -- his astonishment seems genuine.

Unfortunately, the video released by CBS is heavily edited and shows just a small portion of the event. "FYI that was only a tiny piece of it!!" tweeted Cuoco, who promised fans that she is "trying to get you the rest of it!!!!"

The clip does include the joke's final punchline, offered by Parsons after the actors resume their seats on the set.

"Bazinga!"

"The Big Bang Theory" airs Thursdays at 8 p.m. on CBS.