For the first time in its history, the Yale Undergraduate Ballet Company will perform with a live orchestra.

The YUBC will host its fall show tonight and tomorrow night at the Off Broadway Theater. The show, titled “Once Upon a Dream: Classical and Contemporary Extracts,” will incorporate student-choreographed original dances as well as traditional pieces from the Tchaikovsky ballet “The Sleeping Beauty.” YUBC president Nicholas Smith ’16, a coproducer for the show who will also dance the role of the “Bluebird,” said the live orchestra will strongly enhance the performance as a whole.

“Ballet as an art form is so intimately connected to music,” he said. “With a recording, there’s something just a tad artificial.”

A 35-person orchestra — composed of members from student groups such as Yale Symphony Orchestra, Davenport Pops Orchestra and Berkeley College Orchestra — will accompany a 13-ballerina cast. Theresa Oei ’15, one of the show’s directors, said she contacted Rachel Perfecto ’15, the YSO assistant director, to ask her to help assemble a live orchestral ensemble for the show.

Perfecto, who is now the YUBC show’s Orchestral Director, recruited 35 musicians from various groups on campus. Perfecto, Smith and Oei all said that they were excited by the large number of students who were interested in performing in the accompanying orchestra, which is nearly twice the size of the cast of dancers.

“It all came together smoothly,” Perfecto said. “I think [that’s] because few undergraduate musicians at Yale have ever had the opportunity to accompany a ballet.”

Before the open dress rehearsal on Thursday night, the orchestra and the dancers had only rehearsed together twice. Despite the limited time together, dancers and orchestral members interviewed said that the rehearsals had gone smoothly.

Smith noted that in addition to being accompanied by a live orchestra, this weekend’s show will differ from past fall shows in other ways. Normally, he explained, the company will perform a traditional ballet and save their original choreography for the spring show, but the group will dedicate the first half of this year’s show to several dances from “The Sleeping Beauty” and the second half on original choreography.

In combining classical and original dances for this show, Smith said, the YUBC aims to “expose people to the classical, but also bring something new to dancers and the audience … to push them to be more artistic.”

The Off Broadway Theater, where the show is taking place, seats 117 people. There is no orchestra pit, so the orchestra will be positioned on one side of the dance floor. Smith noted that in a break from the traditional ballet performance styles, the orchestra and the dancers will be sharing the stage.

“That’s what ballet companies around the country are doing,” he said. “It goes to show … it’s amazing how collaborative dance is.”

Tchaikovsky’s “The Sleeping Beauty” was first performed in 1890.