Musical theatre is a genre of theatre where music plays a major role in moving the story forward. In addition to the actors, directors, designers, and others who are involved in any professional theatre production, musical theatre requires specialized artists and technicians.

Creating a new musical theatre production requires a composer, who creates the music, and a librettist, who writes the words to the songs (the lyrics). Sometimes this is the same person, and sometimes the librettist also writes any non-singing dialogue (the book). If the performance is entirely sung, it is often called an opera. If there is dialogue, it is often called musical theatre. Many artists and technicians work in both musical theatre and opera, and sometimes dance as well; some individuals and organizations blend all three genres.

If the show has a live orchestra, musicians (sometimes called "pit musicians") are hired to play at every performance. They are led by a conductor, who sets the pace and guides the musicians. Musicians playing for live theatre are usually members of a union.

Before the musicians join the production, which is usually not until the very end of a rehearsal process, an accompanist plays a piano or keyboard during rehearsals so the actors, singers, and dancers can practice.

Some musicals also incorporate dance. Performers can be hired solely to dance, to dance and sing, or to be "triple threats" who dance, sing, and act! A theatrical choreographer creates the dance elements in a play or musical, and often teaches them to actors, singers, and dancers. If there is a lot of dancing in a show, a dance captain will be hired to make sure the choreography remains consistent with the choreographer’s vision, even after many performances.

About the Video: Martha McDonnell, Musician

Martha McDonnell took a break from playing fiddle in Bright Star at the Ahmanson Theatre to talk about her career path and what it takes to work as a musician in the theatre. The most important skills: versatility and diversity in your playing across genres and styles, and the ability to improvise. In this Working in Theatre video, she talks about getting her big break on a Sting musical and acclimating her violin to the theatre before each performance to keep the air conditioning from throwing off its tuning.