Thespis, the first comic opera by Gilbert and Sullivan, premiered at the Gaiety Theatre in London.

Thespis, or The Gods Grown Old, is an operatic extravaganza that was the first collaboration between dramatist W. S. Gilbert and composer Arthur Sullivan. No musical score of Thespis was ever published, and most of the music has been lost. Gilbert and Sullivan went on to become the most famous and successful artistic partnership in Victorian England, creating a string of enduring comic opera hits, including H.M.S. Pinafore, The Pirates of Penzance and The Mikado.

Comic opera, sometimes known as light opera, is a sung dramatic work of a light or comic nature, usually with a happy ending and often including spoken dialogue.

Gilbert and Sullivan refers to the Victorian-era theatrical partnership of the dramatist W. S. Gilbert (1836–1911) and the composer Arthur Sullivan (1842–1900) and to the works they jointly created. The two men collaborated on fourteen comic operas between 1871 and 1896, of which H.M.S. Pinafore, The Pirates of Penzance and The Mikado are among the best known.

The Gaiety Theatre was a West End theatre in Westminster, London, located on Aldwych at the eastern end of the Strand. The theatre was first established as the Strand Musick Hall in 1864 on the former site of the Lyceum Theatre. In 1868, it became known as the Gaiety Theatre and was, at first, known for music hall and then for musical burlesque, pantomime and operetta performances. From 1868 to the 1890s, it had a major influence on the development of modern musical comedy.