James Planché in the context of British Archaeological Association

An extravaganza is a literary or musical work (often musical theatre) usually containing elements of Victorian burlesque, and pantomime, in a spectacular production and characterized by freedom of style and structure. The term is derived from the Italian word stravaganza, meaning extravagance. It sometimes also has elements of music hall, cabaret, circus, revue, variety, vaudeville and mime. Extravaganza came, in the 20th century, to more broadly refer to an elaborate, spectacular, and expensive theatrical production.

Professor Carolyn Wiliams writes that playwrights, producers and critics have often muddled the distinction between burlesque and extravaganza, but she describes the genre this way: "Sexy yet free of "offensive vulgarity", silly yet intelligent, raucus yet spectacularly beautiful, extravaganza was a relatively "high" form of burlesque, intended for an urbane adult audience." She notes that the definition of extravaganza changed during the 19th century, in that a late century extravaganza had a "transformation scene", but earlier it focused on the sexy innuendo and fantasy, often involving fairies, and did not necessarily include a transformation scene. 19th-century British dramatist, James Planché, who was known for his extravaganzas, defined the genre as "the whimsical treatment of a poetical subject."

A principal boy role is the young male protagonist of a play, traditionally filled in theatre by a young actress in boy's clothes.

The earliest example is Miss Ellington who in 1852 appeared in The Good Woman in the Wood by James Planché to the consternation of a reviewer. She was followed by other music hall and burlesque entertainers, such as Harriet Vernon described as "a magnificent creature, who was willing to show her ample figure as generously as the conventional tights and trunks of the day allowed" and thus setting the standard of good legs on display and nominally male costume which emphasized her figure.