The boys, 45 in total, stared forward, waiting for the cue.

The lights dimmed, and the boys of the Arlington High School Varsity Men's Choir began to sing.

It was only rehearsal, but with just one day before the big performance, everything needed to be perfect.

For the first time in history, two Arlington schools- Arlington High School's Varsity Men's Choir and Martin High School Chamber Singers- have been invited to perform the same year at the National Convention of the American Choral Director's Association.

"This is beyond belief,'Martin High School choir director Kay Owens said. "Never before have two schools from one city been selected the same year. It is unheard of until now.'

The choirs were practicing for a 25-minute concert at the Winspear Opera House and a second at the Meyerson Symphony Center the following day.

Some 3,000 professional choral directors and professional musicians from around the world will attend the performances.

Arlington's two choirs were among the 35 selected from 250 submissions. Of the 35 selected, only nine were high schools.

Arlington High choir director Dinah Menger said the Varsity Men's Choir has worked tirelessly since August to perfect the routine, which outlines a boy's life from childhood to adulthood. Among the songs is the popular tune "Some Nights'by the Indie pop band Fun. Associate directors are Mason Barlow and Elizabeth Hilsabeck.

"This group of boys is incredible, hard-working, dedicated,'Menger said. "They deserve this.'

Kole Howie, 18, a senior and four-year member of the Arlington High choir, said he feels honored to be part of the group.

"We are here day after day, during breaks and days off, making music,'said Howie, who plans to major in opera at Indiana University after graduation.

The Martin High School Chamber Singers, with 35 male and female juniors and seniors, will perform a wide-ranging mixture of songs, from a Renaissance ballad to an upbeat Indian tune. Assistant director is Betsy Clark.

Owens, the director, said many of the students juggle the demands of choir with advanced placement courses and other extracurricular activities.

Michael Bailey, 18, a senior, said the group did not initially realize the enormity of the honor it had received.

"Once we realized how big of a deal this was, we got a little nervous,'said Bailey, who plans to major in vocal performance after graduation. "We've been working hard. We're ready to show off what we can do.'