Here's the story behind Second Sunday's choral flashmob on King Street

The Charleston Symphony Orchestra and the Charleston Symphony Chorus surprised the shoppers on King Street at Second Sunday on King with a spontaneous performance of the 'Hallelujah Chorus.'

More than 70 members of the Charleston Symphony Chorus participated in the choral flashmob to promote the Holiday Celebration Concert on December 18th at 7 p.m. at the Gaillard Auditorium.

Production Design Associates were on hand to capture the moment. The video is posted above and the singing kicks in after about 50 seconds.

Saturday's concert will feature more than 120 voices of all ages as well the long awaited return of the Charleston Symphony Orchestra. The concert also features guest soloists from the College of Charleston. Faculty member, David Templeton, will perform Fantasia on Christmas Carols - a hauntingly beautiful medley arranged by Ralph Vaughan Williams. In addition, two of Dr. Taylor's College of Charleston students, Kori Miller and Nathan Matticks will be featured soloists for O Holy Night.

Tickets are on sale now and range from $20 - $45.