April 19, 2021 -- Mills began her acting career as a child and was hailed as a promising newcomer, winning the BAFTA Award for Most Promising Newcomer for her performance in the British crime drama film Tiger Bay (1959), the Academy Juvenile Award for Disney's Pollyanna (1960) and Golden Globe Award for New Star of the Year – Actress in 1961. During her early career, she appeared in six films for Walt Disney, including her dual role as twins Susan and Sharon in the Disney film The Parent Trap (1961).