At any given time in a symphony's performance repertoire, Leonard Bernstein's score to the iconic 1961 blockbuster movie "West Side Story" would be an exceptional offering.

The Baltimore Symphony Orchestra, under the baton of Music Director Marin Alsop, takes the beloved soundtrack a step further Thursday night. In a live, real-time performance, the orchestra plays the music exactly as written, frame by frame, to run in simultaneous accompaniment to the movie that is projected larger than life on a screen over the stage.

This is not a new concept -- the BSO presented the soundtrack to Charlie Chaplin's "Modern Times" last season to rave responses from sold-out houses. However, Chaplin's masterpiece was a silent film: no dialogue, no singing.

"This is a particular challenge for us," said Alsop, whose conducting career took off when she studied under Leonard Bernstein at Tanglewood in 1989. "In this [film] there are a lot of guidelines because the track is not rhythmically even; they didn't [perform] it with a metronome."

In concert
'West Side Story'
» Where: Strathmore, 5301 Tuckerman Lane, North Bethesda
» When: 8 p.m. Thursday
» Info: $33 to $95; 410-783-8000;

Orchestra members wear headphones tuned in to a click track. The click tells them when to play, either in a scene with dialogue or accompanying a song. The music is in front of them and annotated for that purpose.

"This is a new project because until recently the technology didn't exist to break the music out of the film," Alsop pointed out.

"West Side Story" was born as a stage musical in 1957. Stunning for the times, the show featured unforgettable music, groundbreaking dance numbers choreographed by Jerome Robbins and lyrics by Stephen Sondheim.

Perhaps the greatest testament to the show's remarkable and ageless story line is that "West Side Story" transitioned flawlessly from the stage into the 1961 film, which garnered 10 Academy Awards.

"It's great music," Alsop continued. "It's catchy, compelling, clever ... it's got everything."

And for today's young audiences, this technique of live orchestra performance in tandem with the soundtracks of classic films brings the whole experience to a new level of enjoyment.

"This is a nice opportunity to introduce the next generation to the artists, whether it's Leonard Bernstein or Charlie Chaplin, and to keep that connection to these great geniuses of the past," Alsop said.