Lansbury was born to Irish actress Moyna Macgill and English politician Edgar Lansbury, an upper-middle-class family in Regent's Park, central London. To escape the Blitz, in 1940 she moved to the United States with her mother and two brothers, and studied acting in New York City. Proceeding to Hollywood in 1942, she signed with Metro-Goldwyn-Mayer and obtained her first film roles, in Gaslight (1944) and The Picture of Dorian Gray (1945), earning her two Oscar nominations and a Golden Globe Award. She appeared in eleven further films for MGM, mostly in supporting roles, and after her contract ended in 1952 she began supplementing her cinematic work with theatrical appearances. Although largely seen as a B-list star during this period, her appearance in the film The Manchurian Candidate (1962) received widespread acclaim and is cited as being one of her finest performances. Moving into musical theatre, Lansbury finally gained stardom for playing the leading role in the Broadway musical Mame (1966), which earned her a range of awards.