From those in the know, there’s a whisper of anticipation outside Covent Garden Market on Wednesday afternoon. For everyone else, it’s the proverbial calm before the storm as soon club music blares out of a loudspeaker, and a flash mob is unleashed.

For the dancers, performing is akin to a runner’s high.

“I love it,” says Ken Pham, one of the members of the Dynamic Dozen flash mob. “The element of surprise ‘ performing when everyone doesn’t know what’s happening. They’re just having an average day ‘ and we just come out of nowhere and perform.”

What the crowd doesn’t see is the in-depth rehearsal and preparation needed to create a successful flash mob, when people perform a choreographed dance routine in public to the general public’s surprise. Pham iss ecstatic to see the group’s hard work come to fruition.

“We put it together in about three or four days,” he says. “We have full days (of rehearsal). We do spend a lot of time on it ‘ on our own and as a group. Probably about 20 hours total. And we had an hour before (the performance) to review everything.”

The crowd seems transfixed by the acrobatics and slick moves of the participants.

“I thought it was spectacular,” says Jon-Paul McGonigle, one of the unsuspecting people in the crowd. “It was very impactful. Everybody in the market seemed really surprised.”