By Pat Ciarrocchi

PHILADELPHIA (CBS) — When Yannick Neget-Seguin raises his baton, two-hundred fifty performers are engaged across the stage of the Kimmel Center’s Verizon Hall.

Yannick, the dynamic Maestro of the Philadelphia Orchestra, is daring himself in bringing to life a long held dream.

“It was my dream always,” said Yannick. “One of my dreams… to conduct ‘MASS’.

“Bernstein’s MASS”  is legendary composer/conductor Leonard Bernstein’s spiritual rock concert, symphony and Broadway production that challenges faith and makes a plea for peace.

It is rarely performed. But at the Kimmel Center on April 30, May 1,2 and 3, the Philadelphia Orchestra will present “Bernstein’s MASS” for the first time, in its entirety.   

“It is one of the very rare works, where you have to be comfortable in many kinds of style of music,” said Yannick.

The Maestro, who recently signed a seven year renewal with the Orchestra, believes Bernstein is the greatest musical genius of the 20th century.

“MASS” premiered nearly forty years ago.

We found Yannick at this second full rehearsal for “MASS.”  The moving parts are 250 musical artists to accommodate an elaborate score.

“We have the full Philadelphia Orchestra with two choirs. We also have a great cast of mostly Broadway singers,” said Yannick. “There is a main celebrant. There’s some dancers as well. There’s a boys choir, a marching band, even Mummers coming in.”

Though the story line centers on the Catholic Mass, it’s interrupted with reflections about faith and religions, even incorporating Jewish and Middle Eastern rituals.

Yannick is hoping this will be a metaphor for a message of unity for the community.

“We share the beliefs and the anxieties and questioning.. and in the end, we need to live together.

For ticket and performance information on “Bernstein’s MASS,” go to