Hayley Catherine Rose Vivien Mills (born 18 April 1946) is an English actress. She is the daughter of Sir John Mills and Mary Hayley Bell, and the younger sister of actress Juliet Mills. Mills began her acting career as a child and won the BAFTA Award for Most Promising Newcomer for Tiger Bay (1959), the Academy Juvenile Award for Pollyanna (1960), and the Golden Globe Award for New Star of the Year – Actress in 1961.
She appeared in six films for Walt Disney, including a dual role as twins Susan and Sharon in The Parent Trap (1961). In the late 1960s, she began performing in theatrical plays and took on more mature roles. Although she did not maintain her early box office success or Hollywood A-list status, she continued to act in films and television, including the title role in Good Morning, Miss Bliss and as Caroline in Wild at Heart.
United Kingdom