Daisy and Violet Hilton, conjoined twins and entertainers, were born to a barmaid in Brighton, England. Their parents' names are unknown. Accounts vary of the exact year of their birth as well as its circumstances and immediate aftermath, but it is generally believed that their mother, who was unwed, died when they were infants, and their father was reportedly killed during World War I. The twins, who were joined at the base of the spine, were raised by Mary Hilton, the midwife who delivered them. Early on Hilton recognized their earning potential as a circus and vaudeville act at a time when so-called freak shows that exploited human oddities were in their heyday. With Hilton acting as both agent and foster mother, the twins were exhibited at fairs, circuses, and street carnivals. To enhance their act, they were taught to dance and to play the saxophone and violin, and in the years before World War I they toured Germany and then Australia, where they remained for four years.

Mary Hilton brought the twins to the United States in 1916, and for the next thirteen years they performed with various circus troupes and in vaudeville houses while Hilton pocketed most of the money they earned. The twins were reportedly ill-treated by Mary Hilton and kept in a state of poverty, and for a long time they felt powerless to change their fate. Despite this, they were able to maintain positive outlooks through the assistance of the magician Harry Houdini. Houdini, they later claimed, hypnotized them and under hypnosis taught them how to "get rid of each other" and establish individual privacy.

By the end of the 1920s Daisy and Violet had resolved to free themselves from Mary Hilton, and in 1929 they found a sympathetic lawyer who took their case to court. As a consequence Mary Hilton's control over them was severed, and they were at last free to keep their earnings. Daisy and Violet Hilton were now headliners on the American vaudeville circuit, and their joint career blossomed during the 1930s as they performed for Great Depression-era audiences in cities and small towns across the nation. They also appeared in the movies, playing themselves in Freaks (1932), Tod Browning's celebrated melodrama of circus life.

The Hilton twins were not identical. Daisy was a natural blonde and Violet a brunette. In size, however, they were approximately equal. Each twin was 4 feet, 11 inches tall, and their combined adult weight was 190 pounds. After long efforts to find sympathetic officials who would issue marriage licenses, both twins also married, though the unions were short-lived. Violet's marriage to a dancer, James Moore, in 1936 was later annulled. Five years later Daisy married an actor named Harold Estep, who performed under the name Buddy Sawyer; that marriage lasted only ten days.

During the 1940s the career of the Hilton twins declined with the demise of vaudeville, and by the early 1950s their career further regressed as television replaced stage and circus acts as a popular amusement. In 1951 they starred in a B-movie mystery, Chained for Life, playing sisters who must both go to prison for a crime committed by one of them, but that appearance did not give rise to further stage or screen performances. About this time the sisters moved to Florida, where they operated a fruit stand for a number of years. Finally, in 1960 they resettled in Charlotte, North Carolina, where they found jobs weighing produce at a supermarket. After they had not reported to work for several days, they were found dead on the floor at their home, apparently victims of complications from influenza. Public interest in the Hilton sisters revived for a time in 1997, when Sideshow, a musical based on their lives, appeared briefly on Broadway.

Biographical information on the Hilton sisters is largely limited to brief entries in standard reference works. See, for example, Anthony Slide, The Encyclopedia of Vaudeville (1994); Who Was Who on Screen, 3d ed. (1983); and Almanac of Famous People, 8th ed. (2003). For a discussion of conjoined twins, see Luigi Gedda's pioneering study Twins in History and Science (1961). Historical accounts of notable freaks can be found in Frederick Drimmer, Very Special People (1973); Rosemarie Garland Thomson, ed., Freakery: Cultural Spectacles of the Extraordinary Body (1996); and Robert Bogdan, Freak Shows: Presenting Human Oddities for Amusement (1988). See also Bruce Feller, Under the Big Top (1995); and Tom Ogden, Two Hundred Years of the American Circus (1993). The sociocultural and psychological implications of human freaks are discussed in Leslie Fiedler, Freaks: Myths and Images of the Secret Self (1978). An obituary is in the New York Times, 6 Jan. 1969.