Watling was born Dilys Rhys Jones, the daughter of actor Ion Rhys Jones and Patricia Hicks. Ion Rhys Jones was killed in action in World War II, and her mother later married actor Jack Watling.[2]

She attended St Mary's Convent School, Woodford, Essex, followed by acting school. She acted in repertory theatre and at the Bristol Old Vic. Watling was nominated for the Tony Award for Best Leading Actress in a Musical for her Broadway debut in the short-lived Georgy in 1970. It proved to be her sole Broadway credit. Other stage credits include the musical Pickwick (1964), an adaptation of Dickens's The Pickwick Papers; the role of the Beggar Woman in the 1980 London cast of Sweeney Todd in the West End; and the West End multi-media Dave Clark rock musical Time (1986). She also made occasional film appearances, including rôles in the comedy Two Left Feet (1963); crime film, Calculated Risk (film), (also 1963); and the horror film, Theatre of Death, (1967).