Actress, Entertainer. A member of the British theatrical family, Cooper began her career as a singer on Broadway during the 1920s & 1930s.   Sister of actress Violet Kemble-Cooper, Lillian was married to actor/writer Charles Mackay and actor Guy Bates Post.  Actress – 19 films. (bio by: TLS)  Family links:  Spouse:  Guy Bates Post (1875 – 1968)* *Calculated relationship