'Big Bang Theory' Cast Surprises Showrunners With 'Call Me Maybe' Flash Mob (Video)

UPDATED: Co-star Kaley Cuoco came up with the idea and recruited her sister to choreograph the routine in front of a live audience.

The cast of CBS' The Big Bang Theory sure knows how put on a show.

Led by co-star Kaley Cuoco, the Thursday night ratings juggernaut surprised showrunners Chuck Lorre, Bill Prady and Steve Molaro during the Oct. 23 live taping with a coordinated flash mob set to Carly Rae Jepsen's summer hit "Call Me Maybe."

During the bit, the seven cast members -- Kunal Nayyar (Raj), Simon Helberg (Howard), Johnny Galecki (Leonard), Mayim Bialik (Amy), Melissa Rauch (Bernadette), Jim Parsons (Sheldon) and Cuoco (Penny) -- feign surprise when they see the crew break out into dance as they prepare for a take with the trio of showrunners looking on.

PHOTOS: Behind the Scenes: 'The Big Bang Theory'

Ultimately, five of the seven -- save for Galecki and Parsons' notoriously antisocial/neurotic Sheldon -- join the group performing a routine choreographed by Cuoco's sister Bri Cuoco -- to Jepsen's song, much to the showrunners' and live studio audience's pleasure.

The kicker, however, comes when the cast members return to the set's centerpiece couch to find Parsons delivering the ultimate Big Bang Theory icing on the cake: "Bazinga!"

Check out the video, which was filmed during the episode that airs Thursday night and intended as a surprise for the audience and exec producers and the full version -- featuring a mashup of multiple songs -- below.

Email: Lesley.Goldberg@thr.com; Twitter: @Snoodit