Patrons at Barnes and Noble book store in Ontario were treated to a secret flash mob performance by the Crestline High School Show Choir this past weekend.

Crestline Schools Music Teacher Julie Murphy Theodore says the students have been working hard at the performance.

She says the performance was also part of a fundraiser at Barnes and Noble.

A big concert featuring all of the Crestline School choirs is set for 6:30 p.m. on Dec. 17 at Crestline High School and will be the last concert to be held there before the students move to their new building.