When the members of the cast of the Catasauqua High School production of "Big River" had taken their last bows following the fourth and final performance on the afternoon of March 9, heartfelt applause had not yet come to an end.

Most of the students on stage and many of those in the audience had a secret plan.

Cast members called director Robert Fahringer and musical director Richard Milne to the stage to thank them, as is the custom following a final performance.

But there was more.

As the applause died down, a single male singer stood in the audience and began singing, a cappella, the opening lyrics of "Prepare Ye the Way of the Lord." It was a favorite song of the two directors, from the Broadway musical "Godspell," which CHS students had staged under their direction several years ago.

Then another mad stood and sang. And then another.

As the song progressed, dozens of singers, all CHS graduates who had performed in high school productions under Fahringer and Milne, stood and sang, walking to the stage to greet the two surprised men as they did so.

The flash mob performance was in recognition of the fact that Fahringer and Milne will now close the curtain on a 34-year drama directing partnership.

Fahringer took over the drama club in 1980 and has directed over 45 plays and musicals during his career. Although he retired from his position as an English teacher at CHS in June 2013, he returned to direct this final musical.

Milne has been Fahringer's right hand man for all of these years and will retire from his position as choral and instrumental music teacher in June.

CHS grad Hillari Stahler was among the organizers of the surprise.

"These two teachers have not only produced stellar musical productions but they have inspired countless students along the way," she told The Press.

Fahringer has a reputation for getting students unfamiliar with acting and singing to take on the challenge of the high school shows he directed.

"It was not uncommon for him to convince the quarterback of the football team to take on the leading role in the play," Stahler said. "He also inspired students to come out of their shell by involving them in productions through building sets, and doing work back stage."

Stahler said Fahringer had a profound affect on her life.

"I, like many other Catty grads, pursued a career in the arts because of the many positive experiences I had in drama club," she said. And, she met her future husband while rehearsing and performing "Fiddler on the Roof."

"We felt like we needed to give back," she said.

In addition to planning the flash mob, she set up a Facebook page and invited former students to leave a message on a You Tube channel dedicated to Fahringer and Milne. Before long a committee was formed and a reception was planned for former students to greet the two men after the performance.

A total of about 100 current and past drama students rehearsed the song they sang after the final matinee performance.